From the given options, select the one that rightly explains the expression:
“Once in a blue moon”
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Very rarely
The idiom once in a blue moon means very rarely. A "blue moon" is a second full moon within one calendar month, which happens only about once in two or three years, so something that happens once in a blue moon hardly ever happens.
Example: My uncle lives abroad and visits us only once in a blue moon.