答案：B

题目分析：通过分析句子结构，可知这个句子中包含一个同位语从句。Request后的同位语从句常用“should + 动词原形”，should可以被省略，故选B。

点评：表示请求、要求、命令、建议等名词advice, desire, decision, idea, instruction, order, plan, proposal, recommendation, request, requirement, suggestion, wish充当句子的主语而后面接表语从句或它们后面接同位语时，表语从句及同位语从句都须用虚拟语气。其虚拟语气的结构为：(should)  + 动词原形。如：We followed his advice that we should ask our teacher for help.