A proposal is revoked:
(1) By communication of notice of revocation by the proposer to the other party in the manner prescribed for communication of consent and acceptance, before his acceptance has been communicated to the former;
(2) By the lapse of time prescribed in such proposal for its acceptance, or if no time is so prescribed, the lapse of a reasonable time without communication of acceptance;
(3) By the failure of the acceptor to fulfill a condition precedent to acceptance; or
(4) By the death or mental illness of the proposer before acceptance of the proposal.