— How are you getting along with your project?

— I was about to give up when an idea occurred to me ____ I could work with my roommate Tim. [ ]

A. that

B. how

C. why

D. whether

在出口信用保险中，保险单对被保险人向某特定买方出口货物所承担的最高赔偿限额称为保证金额。