Which of the following tag questions is INCORRECT？A．There is no doubt about it, is it？B．No

Which of the following tag questions is INCORRECT？

A．There is no doubt about it, is it？

B．No one was hurt, were they？

C．She seldom goes to the theatre, does she？

D．I don"t think he is bright, is he？

请帮忙给出正确答案和分析，谢谢！