'Cry over spilt milk' means
ACry while drinking milk
BRegret what cannot be undone
CBe careless with food
DForgive easily
Answer & Solution
Correct answer: B. Regret what cannot be undone
1. Once milk is spilt, it cannot be recovered.
2. Crying over it is futile regret.
3. Hence option A.
_Source: jkchrome.com SSC Idioms and Phrases PDF (Mistral OCR), section on common idioms_