(1) An offer lapses when
the party to whom it is made fails to accept it within the time or in the manner prescribed by the offeror, or, if no time or manner is prescribed, within a time or in a manner reasonable under the circumstances,
the offeree communicates his refusal of the offer, or makes a counter-offer,
either party dies or, in case of a corporation, ceases to exist.
(2) An oral offer must be accepted immediately unless the circumstances indicate otherwise.
(3) A late acceptance is effective as an acceptance if without undue delay the offeror informs the offeree that the offeror is treating it as an effective acceptance.