问题详情

Which of the following italicized parts is a subject clause(主语从句)？

A．Dancing is an activity where sight matters more than hearing.

B．The first thing is to find out where she is.

C．You"d better not leave the medicine where kids can get at it.

D．It"s really no business of yours where I spend my summer vocation.

请帮忙给出正确答案和分析，谢谢！