So engrossed in his efforts would Gaugin become that he barely noticed the passing of time.

A．delighted in

B．frustrated by

C．expanded by

D．involved in

甲于5月20日交付一辆奔驰车供乙试用，试用期2周，下面以此为例分析如下：

（1）、在试用期间，发生风险，应由（）负担。

（2）、试用期届满，乙表示买下，其后发生风险，应由（）负担

A.甲、甲

B.乙、乙

C.甲、乙

D.乙、甲