Question

What is castles in the air an example of?

Idiom
Paradox
Symbol
Irony

Answer 1

I think it's A, idiom, because castles cannot really be in the air.

Answer 2

The answer is: [A]: Idiom.
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The phrase: "castles in the air" is an idiom.
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Explanation: "Castles in the air", literally speaking, are impossible to exist or be created.
So, when used as an idiomatic phrase, it refers to events that cannot, or likely will not, be possible to achieve.
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