diff --git a/mesonbuild/mconf.py b/mesonbuild/mconf.py
index 42028307b61b..a7cbd2b5e01b 100644
--- a/mesonbuild/mconf.py
+++ b/mesonbuild/mconf.py
@@ -48,8 +48,6 @@ def add_arguments(parser: 'argparse.ArgumentParser') -> None:
                         help='Clear cached state (e.g. found dependencies)')
     parser.add_argument('--no-pager', action='store_false', dest='pager',
                         help='Do not redirect output to a pager')
-    parser.add_argument('-A', action='append', dest='A',
-                        help='Add a subproject option.')
     parser.add_argument('-U', action='append', dest='U',
                         help='Remove a subproject option.')
 
@@ -358,8 +356,6 @@ def print_augments(self) -> None:
 def has_option_flags(options: T.Any) -> bool:
     if options.cmd_line_options:
         return True
-    if options.A:
-        return True
     if hasattr(options, 'D') and options.D:
         return True
     if options.U:
@@ -386,10 +382,6 @@ def run_impl(options: CMDOptions, builddir: str) -> int:
 
         save = False
         if has_option_flags(options):
-            if hasattr(options, 'A'):
-                A = options.A
-            else:
-                A = []
             if hasattr(options, 'U'):
                 U = options.U
             else:
@@ -397,7 +389,7 @@ def run_impl(options: CMDOptions, builddir: str) -> int:
             all_D = options.projectoptions[:]
             for keystr, valstr in options.cmd_line_options.items():
                 all_D.append(f'{keystr}={valstr}')
-            save |= c.coredata.optstore.set_from_configure_command(all_D, A, U)
+            save |= c.coredata.optstore.set_from_configure_command(all_D, U)
             coredata.update_cmd_line_file(builddir, options)
         if options.clearcache:
             c.clear_cache()
diff --git a/mesonbuild/options.py b/mesonbuild/options.py
index 93244a95474a..f998780bafa4 100644
--- a/mesonbuild/options.py
+++ b/mesonbuild/options.py
@@ -790,7 +790,6 @@ def get_value_for(self, name: 'T.Union[OptionKey, str]', subproject: T.Optional[
         vobject, resolved_value = self.get_value_object_and_value_for(key)
         return resolved_value
 
-
     def num_options(self):
         basic = len(self.options)
         build = len(self.build_options) if self.build_options else 0
diff --git a/unittests/linuxliketests.py b/unittests/linuxliketests.py
index 6b4223894227..b242e8ba441a 100644
--- a/unittests/linuxliketests.py
+++ b/unittests/linuxliketests.py
@@ -1883,7 +1883,7 @@ def test_persp_options(self):
         self.check_has_flag(compdb, sub2src, '-O1')
 
         # Set subproject option to O2
-        self.setconf(['-Dround=2', '-A', 'sub2:optimization=3'])
+        self.setconf(['-Dround=2', '-D', 'sub2:optimization=3'])
         compdb = self.get_compdb()
         self.check_has_flag(compdb, mainsrc, '-O1')
         self.check_has_flag(compdb, sub1src, '-O1')
@@ -1897,7 +1897,7 @@ def test_persp_options(self):
         self.check_has_flag(compdb, sub2src, '-O2')
 
         # Set top level option to O3
-        self.setconf(['-Dround=4', '-A:optimization=3'])
+        self.setconf(['-Dround=4', '-D:optimization=3'])
         compdb = self.get_compdb()
         self.check_has_flag(compdb, mainsrc, '-O3')
         self.check_has_flag(compdb, sub1src, '-O1')
diff --git a/unittests/optiontests.py b/unittests/optiontests.py
index 635d1ec9ea30..304a922f2254 100644
--- a/unittests/optiontests.py
+++ b/unittests/optiontests.py
@@ -118,24 +118,24 @@ def test_augments(self):
         self.assertEqual(optstore.get_value_for(name, sub2_name), top_value)
 
         # First augment a subproject
-        optstore.set_from_configure_command([], [f'{sub_name}:{name}={aug_value}'], [])
+        optstore.set_from_configure_command([f'{sub_name}:{name}={aug_value}'], [])
         self.assertEqual(optstore.get_value_for(name), top_value)
         self.assertEqual(optstore.get_value_for(name, sub_name), aug_value)
         self.assertEqual(optstore.get_value_for(name, sub2_name), top_value)
 
-        optstore.set_from_configure_command([], [], [f'{sub_name}:{name}'])
+        optstore.set_from_configure_command([], [f'{sub_name}:{name}'])
         self.assertEqual(optstore.get_value_for(name), top_value)
         self.assertEqual(optstore.get_value_for(name, sub_name), top_value)
         self.assertEqual(optstore.get_value_for(name, sub2_name), top_value)
 
         # And now augment the top level option
-        optstore.set_from_configure_command([], [f':{name}={aug_value}'], [])
+        optstore.set_from_configure_command([f':{name}={aug_value}'], [])
         self.assertEqual(optstore.get_value_for(name, None), top_value)
         self.assertEqual(optstore.get_value_for(name, ''), aug_value)
         self.assertEqual(optstore.get_value_for(name, sub_name), top_value)
         self.assertEqual(optstore.get_value_for(name, sub2_name), top_value)
 
-        optstore.set_from_configure_command([], [], [f':{name}'])
+        optstore.set_from_configure_command([], [f':{name}'])
         self.assertEqual(optstore.get_value_for(name), top_value)
         self.assertEqual(optstore.get_value_for(name, sub_name), top_value)
         self.assertEqual(optstore.get_value_for(name, sub2_name), top_value)
@@ -154,8 +154,8 @@ def test_augment_set_sub(self):
                              ['c++98', 'c++11', 'c++14', 'c++17', 'c++20', 'c++23'],
                              top_value)
         optstore.add_system_option(name, co)
-        optstore.set_from_configure_command([], [f'{sub_name}:{name}={aug_value}'], [])
-        optstore.set_from_configure_command([f'{sub_name}:{name}={set_value}'], [], [])
+        optstore.set_from_configure_command([f'{sub_name}:{name}={aug_value}'], [])
+        optstore.set_from_configure_command([f'{sub_name}:{name}={set_value}'], [])
         self.assertEqual(optstore.get_value_for(name), top_value)
         self.assertEqual(optstore.get_value_for(name, sub_name), set_value)