It is our belief ________ we will find a cure for cancer in the

It is our belief ________ we will find a cure for cancer in the next ten years.
A、whether
B、which
C、what
D、that
【正确答案】：D
【题目解析】：we will find...是一个同位语从句，修饰说明belief的内容，从句结构及意义都是完整的，故用that引导。