If a local department is a child’s guardian under this subtitle, a juvenile court: retains jurisdiction until: the child attains 18 years of age; or the juvenile court finds the child to be eligible for emancipation; and may continue jurisdiction until the child attains 21 years of age. If a juvenile court designates an individual as a child’s guardian, the juvenile court: may retain jurisdiction until the child attains 18 years of age; or on finding further review unnecessary to maintain the child’s health and welfare, may terminate the case before the child attains 18 years of age. An order for adoption of a child terminates the child’s guardianship case. On termination of a guardianship case, a juvenile court shall close the case. Notwithstanding subsections (a) and (b) of this section, if the court enters an order directing the provision of services to a child under § 5–324(b)(1)(ii)7B of this subtitle, the court retains jurisdiction to rule on any motion related to the enforcement, modification, or termination of the order, for as long as the order is effective.