下面代码段的运行结果是(______) class A: def __new__(self): self.__init__(self) print("A's __new__() invoked") def __init__(self): print("A's __init__() invoked") class B(A): def __new__(self): print("B's __new__() invoked") def __init__(self): print("B's __init__() invoked") def main(): b = B() a = A() main() A. B's __new__() invoked A's __init__() invoked B. B's __new__() invoked A's __new__() invoked C. B's __new__() invoked A's __init__() invoked A's __new__() invoked D. A's __init__() invoked A's __new__() invoked