Option (1) is correct: Under Section 31 of the Indian Contract Act, 1872, a 'contingent contract' is a contract to do or not to do something, if some event, collateral to such contract, does or does not happen. It is a valid contract.
Option (2) is incorrect: It is not a voidable contract.
Option (3) is incorrect: It is not void ab initio.
Option (4) is incorrect: It does not become void when the event becomes impossible.