A day is considered a rainy day when it receives a rainfall of:

Correct option is C

✅ (c) 2.5 mm: • As per Indian Meteorological Department (IMD), a day is classified as rainy if rainfall is ≥ 2.5 mm in 24 hours. • This is the minimum measurable limit for effective rainfall events.
❌ (a) 3.0 mm: • Above the threshold, but 2.5 mm is the standard baseline.
❌ (b) 2.0 mm: • Below the required minimum.
❌ (d) 12.5 mm: • This would be a moderate rain, but not the definition of a rainy day threshold.