Final answer:
The nurse's best recommendation for this situation would be to refer the child to a developmental specialist for further evaluation
Step-by-step explanation:
The nurse's best recommendation for this situation would be to refer the child to a developmental specialist for further evaluation (option b).
At 18 months old, it is concerning that the child hits siblings and has limited verbal communication, only saying "No." These behaviors may be indicators of developmental delays or difficulties. Therefore, it would be beneficial to have the child evaluated by a specialist who can assess their development more comprehensively and provide appropriate interventions or recommendations to address the concerns.