—I don't know why Denise started crying when I mentioned the wedding.

—It ______ what you said about her brother. Or, perhaps she is just nervous. [ ]

A. should have been  

B. couldn't have been

C. could have been

D. must have been

小林坐在行驶的汽车上，以他乘坐的汽车为参照物，他是______的．（选填“运动”或“静止”）