you have no idea what a trouble i had ____you this present A,find B to find C finding D found

题目

you have no idea what a trouble i had ____you this present A,find B to find C finding D found
答案是c
为什么？？？

答案

如果选择to find,是为了找到这个礼物
选择C.finding,意思是找到这个礼物,强调结果
不过,你的句子中有错误,不能说what a trouble,要说what trouble
You have no idea what trouble I had (finding) you this present.
你不知道我给你找到这个礼物费了多大的力气.