Four classes form a diamond: B and C both inherit from A, and D inherits from both. class A: def who(self): return "A" class B(A): def who(self): return "B" + super().who() class C(A): def who(self): return "C" + super().who() class D(B, C): def who(self): return "D" + super().who() print(D().who(), [k.__name__ for k in D.__mro__]) What does the program print?