What does the expression once in a blue moon mean?

• A. Often
• B. Never
• C. Occasionally or rarely occurring
• D. At exactly midnight

Answer: (C)

This phrase signals that something happens infrequently. It’s used to describe events that occur only on rare occasions, not often and not never. So the best fit is “Occasionally or rarely occurring.” The other options don’t match: often means frequent, which is opposite; never would imply zero occurrences, which isn’t what the idiom conveys; and at exactly midnight is irrelevant to frequency and timing. A simple example: “I visit once in a blue moon” means you visit only very rarely.