Subject to subsections (b) and (c) of this section and except as prohibited under §§ 4–505 and 4–506 of this subtitle, in accordance with the order of priority listed, a member of one of the following classes of individuals who is reasonably available may make an anatomical gift of a decedent’s body or part for the purpose of transplantation, therapy, research, or education: An agent of the decedent at the time of death who could have made an anatomical gift under § 4–503(b) of this subtitle immediately before the decedent’s death; The persons who were acting as the guardians of the decedent at the time of the death of the decedent; The spouse or domestic partner of the decedent; The adult children of the decedent; The parents of the decedent; The adult siblings of the decedent; The adult grandchildren of the decedent; The grandparents of the decedent; An adult who exhibited special care and concern for the decedent; or Another person having the authority to dispose of the body of the decedent. If there is more than one member of a class listed in subsection (a)(1), (3), (4), (5), (6), (7), or (9) of this section entitled to make an anatomical gift, an anatomical gift may be made by a member of the class unless that member or a person to which the gift may pass under § 4–509 of this subtitle knows of an objection by another member of the class. If an objection to an anatomical gift is known, the gift may be made only by a majority of the members of the class who are reasonably available. A person may not make an anatomical gift if, at the time of the decedent’s death, a person in a prior class under subsection (a) of this section is reasonably available to make or to object to the making of an anatomical gift.