Which of the following is NOT an imperative sentence？A．Let"s take a taxi, shall we？B．Pleas

Which of the following is NOT an imperative sentence？

A．Let"s take a taxi, shall we？

B．Please let us have more time, will you？

C．Take a seat, will you？

D．Helen plays on my side, doesn"t she？

请帮忙给出正确答案和分析，谢谢！