is often the case with a new idea ,much preliminary activity and optimistic disscussion priduce no c

题目

is often the case with a new idea ,much preliminary activity and optimistic disscussion priduce no concrete proposals.A,that B,it C,which D,as 选D可是为什么?

答案

前半句不能是一个完整的句子,所以排除A和B,as作为物主代词可以放句首,which只能作为具体指代