What is one domestic use of rivers?

Correct answer: Water for drinking and cleaning

The direct answer is A, water for drinking and cleaning. Rivers are important sources of freshwater, although water must be treated before it is safely used for drinking. At home, water is needed for drinking, cooking, washing, bathing, and cleaning. Option A is correct because these are genuine domestic uses. Option B is impossible and has no geographical meaning: mountains cannot be cut into air. Option C is impossible because rivers cannot cool the Sun. Option D is wrong because rivers do not dry up the sea; river water generally flows toward seas or oceans. The question asks for one household use, so a practical daily activity is required. Memory cue: domestic use means home use—drink, cook, wash, and clean.