In a fully developed term infant, at age 6 weeks the nurse practitioner should expect the triangular-shaped posterior fontanel to be:

Rationale: A. The posterior fontanel, which is triangular in shape, typically closes by 6–8 weeks of age in a full-term infant. Closure at this age is considered normal and indicates appropriate cranial development. B. While some posterior fontanels may remain slightly open beyond 6 weeks, persistent patency is uncommon and may warrant evaluation. C. A pulsatile posterior fontanel is more characteristic of the anterior fontanel in a normal infant and is not typical for the posterior fontanel. D. An open and pulsatile posterior fontanel at 6 weeks is unusual and may suggest delayed closure or underlying pathology.