S.D. Codified Laws § 29A-5-304
Any individual who has sufficient capacity to form a preference may at any time nominate any individual or entity to act as his guardian or conservator. The nomination may be made in writing, by an oral request to the court, or may be proved by any other competent evidence. The court shall appoint the individual or entity so nominated if the nominee is otherwise eligible to act and would serve in the best interests of the protected person. If a person alleged to be in need of protection has designated an individual to serve as guardian or conservator under a validly executed legal instrument, including a power of attorney, and the court does not appoint the designated individual, the court shall issue written findings of fact and conclusions of law as to why the designated individual was not appointed.
In the absence of an effective nomination by the protected person, the court shall appoint as guardian or conservator the individual or entity that will act in the protected person's best interests. In making that appointment, the court shall consider the proposed guardian's or conservator's geographic location, familial or other relationship with the protected person, ability to carry out the powers and duties of the office, commitment to promoting the protected person's welfare, any potential conflicts of interest, and the recommendations of the spouse, the parents or other interested relatives, whether made by will or otherwise. The court may appoint more than one guardian or conservator and need not appoint the same individual or entity to serve as both guardian and conservator.
SDCL 29A-5-304