The King of Prussia ________ that his greatest gift would have such a strange history.

A.hadn't had imagined

B.shouldn't have imagined

C.mustn't have imagined

D.couldn't have imagined

答案及解析： D

解析：

couldn't have done指对过去的一种否定猜测，符合语境。shouldn't have done指"过去不应该做某事却做了"；

mustn't表禁止。