South Dakota Codified Laws
Chapter 07 - Communication Of Proposal And Acceptance
Section 53-7-5 - Acceptance of proposal, communication.

53-7-5. Acceptance of proposal, communication.
If a proposal prescribes any conditions concerning the communication of its acceptance, the proposer is not bound unless they are conformed to; but in other cases any reasonable and usual mode may be adopted.

Source: CivC 1877, §893; CL 1887, §3517; RCivC 1903, §1211; RC 1919, §826; SDC 1939, §10.0317.