下面代码的输出结果是？list1 = [(m,n) for m in 'ABC' for n in 'ABC' if m != n]print(list1)

A、['AC','AD','BC','BD'];
B、[('A','C'),('A','D'),('B','C'),('B','D')];
C、错误;
D、[('A','B'),('A','C'),('B','A'),('B','C'),('C','A'),('C','B')]