Final answer:
A visit from a parent would provide the best support for an adolescent client who is withdrawn because warm parent-child relationships are important for the well-being of teenagers, even as they seek independence from their family.
Step-by-step explanation:
The nurse correctly understands that providing the best support for an adolescent client who is withdrawn and unwilling to eat might be a visit with a parent. Developmentally, adolescents are in the process of forming their identities and while their peer group becomes increasingly important, parental support and a warm relationship with parents are associated with positive outcomes. Even as teenagers seek independence, the presence of a parent can provide a sense of security and familiarity that may be comforting in a hospital setting. Therefore, a visit from a parent could help the adolescent feel more supported and may encourage interaction and eating, contributing to their recovery.