Select the most appropriate meaning of the given idiom:
"A pipe dream."

Correct option is A

Option (a) is the correct meaning of the given idiom.
A pipe dream: A plan or wish that is unrealistic and unlikely to be achieved.
Example: Expecting to become a billionaire overnight is just a pipe dream.
Other related idioms:
· "Castles in the air" – Unrealistic dreams or plans.
· "Cry for the moon" – To desire something impossible.
· "Fool’s paradise" – A state of false happiness.