7610. The tour was cancelled on account of incessant rain.

✅ The correct answer is option A.
Constant : occurring continuously over a period of time.

Heavy : of great weight; difficult to lift or move.

Intermittent : occurring at irregular intervals; not continuous or steady.

Unexpected : not expected or regarded as likely to happen.

Incessant : (of something regarded as unpleasant) continuing without pause or interruption.

Synonym of Incessant is Constant