'When pigs fly' means
ASomething pleasant
BSomething that happens often
CSomething that will never happen
DSomething painful
Answer & Solution
Correct answer: C. Something that will never happen
1. Pigs cannot fly.
2. Idiom mocks an impossible event.
3. Means 'will never happen'.
4. Hence option A.
_Source: jkchrome.com SSC Idioms and Phrases PDF (Mistral OCR), section on common idioms_