Select the most appropriate meaning of the highlighted idiom in the given sentence.
You must have a concrete project and not build castles in the air if you want to submit an application for a loan.

Correct option is C

The correct meaning of the idiom "build castles in the air" in the given sentence is "have unrealistic ideas."
· "Build castles in the air" refers to forming plans or dreams that are unlikely or impractical, much like constructing imaginary castles in the sky.
· Example: While I appreciate his creativity, his business plans often seem like he’s building castles in the air.
· Other options:
· (a) make unfaithful friends and (d) make unplanned buildings do not relate to the meaning of the idiom.
· (b) talk irresponsibly is close but doesn't capture the full essence of fantasizing or daydreaming, which is central to the idiom.