Correct Answer: Desert

Solution : The second option is the correct choice.

"Abandon" means to leave or give up completely.
"Desert" also means to abandon or forsake. In the context of synonyms, "desert" aligns closely with the meaning of abandoning or leaving something behind.

The meanings of the other options are:

Perish: It denotes to suffer death or complete destruction; to die.

Prolong: It denotes extending the duration or existence of something; to lengthen.

Retain: It means to keep or continue to have possession or control of something.

Therefore, "Desert" is the most suitable synonym for "Abandon" among the options provided.