Subject to subsection (c) of this section, a transfer may be made only for 1 minor, and only 1 person may be the custodian. All custodial property held under this subtitle by the same custodian for the benefit of the same minor constitutes a single custodianship. Notwithstanding any provision of this subtitle to the contrary, 2 persons may be designated as custodians of custodial property for the benefit of the same minor and that arrangement shall constitute a single custodianship. If 2 persons are designated as custodians, they shall act as joint custodians under this subtitle and, unless specified otherwise in any document creating the custodianship, each joint custodian shall have the full power and authority to act alone as a custodian under this subtitle. If either joint custodian resigns, dies, becomes incapacitated, or is removed, the remaining custodian may serve as sole custodian without the necessity of appointing a successor joint custodian.