The Mother of a 16-Week-Old Infant Calls the Clinic, Concerned

The mother of a 16-week-old infant calls the clinic, concerned because she cannot feel the posterior fontanelle on her infant. Which response by the nurse would be most appropriate?

A) "It is normal for the posterior fontanelle to close by 8-12 weeks after birth."
B) "Bring your infant to the clinic immediately."
C) "This is due to overriding of the cranial bones during labor."
D) "Your baby must be dehydrated."