The following individuals or entities may represent an individual Indian landowner:

(a) An adult with custody acting on behalf of his or her minor children;

(b) A guardian, conservator, or other fiduciary appointed by a court of competent jurisdiction to act on behalf of an individual Indian landowner;

(c) An adult or legal entity who has been given a written power of attorney that:

(1) Meets all of the formal requirements of any applicable tribal or state law;

(2) Identifies the attorney-in-fact and the land to be leased; and

(3) Describes the scope of the power granted and any limits thereon.