she was interested in ----- she has seen at the exhibition 选哪一个

问题描述:

she was interested in ----- she has seen at the exhibition 选哪一个
a which b all what c all which d what
请翻译一下句子意思 并且说说选择的理由

宾语从句what就够了,要么all that,all是先行词,that引导定语从句,which不行.