The reason why I gave in is if I didn’t.
A. because she would be disappointed
B. that she would be disappointed
C. because she would have a disappointment
D. for she would be disappointed
网友回答
A. because she would be disappointed
B. that she would be disappointed
C. because she would have a disappointment
D. for she would be disappointed
解析：主语是reason时,表语从句用that 引导。