I couldn't help ____ when I saw that.

I couldn't help ____ when I saw that.
A、laugh
B、laughed
C、laughing
D、to laugh
【正确答案】：C
【题目解析】：【考点点击】本题考查can' 't help doing sth.的用法。【要点透析】can' 't help doing sth.意为“情不自禁地做某事”。本句意为:当我看到那时,我情不自禁地笑了。