The correct option is C had a whale of a time
An idiomatic expression is a type of informal English where the meaning
of the expression is different than the literal meaning of the
expression.
Option C: The idiom "had a whale of a time" means 'to have an exceptionally fun, exciting and amusing experience'. It relates to the conversation, (enjoy last night's party) hence C is correct.
Option A: The idiom means 'it is the appropriate time', this meaning is not relevant to the sentence, hence this option is incorrect.
Option B: 'Behind the times' means 'behaving in an outdated or unpopular way'; it does not provide the required meaning to the conversation. Hence B is incorrect.
Option D: 'A hell of a time' describes something that is very difficult or unpleasant. It has an opposite meaning to the context of the sentence, which has the words "did you enjoy... Absolutely!". Hence D is incorrect.