— I left my handbag on the train, but luckily someone gave it to a railway official.

— How unbelievable to get it back! I mean, someone _____ it. [ ]

A. will have stolen

B. might have stolen

C. should have stolen

D. must have stolen

甲、乙工程承包单位组成施工联合体参与某项目的投标，中标后联合体接到中标通知书，但尚未与招标人签订合同，联合体投标时提交了10万元投标保证金。此时两家单位认为该项目盈利太少，于是放弃该项目，对此，招标投标法的相关规定是 。

A．10万元投标保证金不予退还

B．可以退还5万元投标保证金

C．若未给招标人造成损失，可退还10万元投标保证金

D．若未给招标人造成损失，可以退还5万元投标保证金