He paid the boy 10 dollars for washing ten windows ,most of___had not been cieaned for years

问题描述:

He paid the boy 10 dollars for washing ten windows ,most of___had not been cieaned for years
A them B those C that D which我认为答案是A 可是为什么是D 求详解

most of是一个定语从句,需要用代词,空格处指代的是物体ten windows,所以要用指代物体的代词which.