(1) An adoption decree may not be entered if the child who is the subject of an adoption proceeding is not legally free for adoption.
(2) A child may be placed for adoption only by:
(a) the department or another agency to which the child has been relinquished for purposes of adoption;
(b) the department or another agency expressly authorized to place the child for adoption by a court order terminating the relationship between the child and the child's parent or guardian;
(c) the child's parents; or
(d) a guardian expressly authorized by the court to place the child for adoption.