The agency will make payment to a representative payee—

1. (a) If payments are due to a minor under the age of 18; or
2. (b) If payments are due to an annuitant or survivor who is mentally incompetent or under other legal disability; or
3. (c) If payments are due to an annuitant when the annuitant is physically or mentally incapable of managing or directing the management of his or her benefit.