A defendant may plead:
Except as otherwise specifically provided, a plea of guilty or nolo contendere can only be entered by a defendant himself in open court. If a defendant refuses to plead, or if the court refuses to accept a plea of guilty or nolo contendere, the court shall enter a plea of not guilty. The court may not enter a judgment unless it is satisfied that there is a factual basis for any plea except a plea of nolo contendere.
SDCL 23A-7-2