Select the most appropriate meaning of the highlighted idiom in the given sentence.
My elder brother is so innocent that winning an argument against him is like shooting fish in a barrel.

Correct option is B

Option (b) is the correct meaning of the given idiom.
Shooting fish in a barrel: This idiom means something that is extremely easy to accomplish. It refers to the idea that shooting fish in a confined space, like a barrel, would require little effort and skill.
Example: Beating the amateur team was like shooting fish in a barrel for the national champions.
Other related idioms and their meanings:
· Piece of cake – Something very easy to do.
· Walk in the park – A task that is very easy to complete.