If Henry ______ under the ladder to catch her when she fell, she couldnt be smiling like t

If Henry ______ under the ladder to catch her when she fell, she couldnt be smiling like this now.

A．didn"t stood

B．hadn"t stood

C．doesn"t stood

D．hasn"t stood

请帮忙给出正确答案和分析，谢谢！