If I can help___________, I don't like working late into the nig

If I can help___________, I don't like working late into the night.
A、so
B、That
C、it
D、them
【正确答案】：C
【题目解析】：本题中it用来指代某一件事情。if I can help it是一种习惯说法，意思是“如果我有办法”。句意为:“如果我有办法，我不想工作到深夜。”