She felt very upset what her deskmate said.A because B because of C as if D unless

问题补充：

She felt very upset what her deskmate said.

A because B because of C as if D unless

答案：

解析：这题考察句子结构: what her deskmate said,是名词性从句,所以填because of”因为”,其它选项都是借状语从句,句意是:因为同桌说的话,她感到不安.选B.