4.It is said that the early European playing-cards ____ for entertainment and education.

A．were being designed

B．have designed

C．have been designed

D．were designed

甲与乙发生口角后，乙声称要把甲杀死，并去商店买了一把匕首，甲怕乙杀死自己，就在乙从商店回来的路上，用猎枪打死了乙，甲的行为属于( )。

A．正当防卫

B．防卫过当

C．故意犯罪

D．假想防卫