The search for the lost ship must be__ because of poor weather.

C. be abandoned 是被动语态。。。。楼上的解释。。。。

abandon = give up (an action or practice) completely.

release 释放
resign 辞职，使...屈从
surrender 投降

D.give up 的意思。由于天气不好打捞沉船的事情只好搁浅了。

B. Resigned

resign

v. quit an office or position; relinquish, give up, abdicate; submit to, quietly accept

D I guess.
A 释放的
B 听天由命的
C 被抛弃的
D 放弃的

选C 放弃的意思