(23) Parent.--The term `parent' means--

(A) a natural, adoptive, or foster parent of a child (unless a foster parent is prohibited by State law from serving as a parent);

(B) a guardian (but not the State if the child is a ward of the State);

(C) an individual acting in the place of a natural or adoptive parent (including a grandparent, stepparent, or other relative) with whom the child lives, or an individual who is legally responsible for the child's welfare; or

(D) except as used in sections 615(b)(2) and 639(a)(5), an individual assigned under either of those sections to be a surrogate parent.