单选题When they went into 

问题补充：

When they went into the shop and asked to look at the engagement rings, the girl brought out a cheaper one, __she had arranged with James.A.the which was whatB.what was at C.which was whatD.that was that

答案：

C解析C。which 引导一个非限制性定语从句，其中 which 指代 a cheaper one，且在定语从句中用作主语。which was what 中的 what引导一个表语从句，它相当于 the one that。