If an offer is made by letter, an acceptance by written reply takes effect from the time it is sent and not from the time it is received; hence, withdrawal of the offer by the offeror after that time is ineffective. Ifan offer contains alternative propositions, the party receiving the offer may elect between the alternative propositions. (Orig. Code 1863, § 2690; Code 1868, § 2686; Code 1873, § 2728; Code 1882, § 2728; Civil Code 1895, § 3646;
Civil Code 1910, § 4231; Code 1933, § 20-114.)