问题详情

Why did the subjects in the study have to be married？
A．Because the researchers wanted to find out the effects blood pressure had on marriage
B．Because the researchers wanted to find out the effects of marriage on heart walls.
C．Because the researchers wanted to find out the effects marriage had on blood pressure
D．Because the researchers wanted to find out the effects heart walls had on marriage.请帮忙给出正确答案和分析，谢谢！