do you know the boy the dictionary _____is very expensive.为什么选a A . of whom Bof which C whose D that

Question

do you know the boy the dictionary _____is very expensive.
为什么选a A . of whom Bof which C whose D that

Answer 1

the dictionary of whom是从句的主语.whom指代前文的boy,因为前面有of所以用宾格.
如果想要选B,which不能指代人.
想选C,那么原文应该是whose dictionary,顺序应该是这样的,而且不能有定冠词the,因为whose有种形容词性物主代词的意味.
如果选D,笑话,那么the boy 和the dictionary有一个就是无用的句子成分了.