It was decided to the search when there was no hope of finding the missing girl alive.A.

问题补充：

It was decided to the search when there was no hope of finding the missing girl alive.

A. call off

B. take up

C. keep off

D. ring up

答案：

(答案→)A. call off

B. take up

C. keep off

D. ring up

解析：call off(=cancel)取消符合句意。