Final answer:
The best response for a nurse to provide reassurance to a mother concerned about her son's behavior and mood changes is to listen and address specific concerns, fostering an environment of open communication.
Step-by-step explanation:
The nurse's response should always aim to provide comfort, clarify patient concerns, and engage in a constructive dialogue that can lead to better understanding and care. When the mother of the child asks the nurse for reassurance about her son's condition, the most appropriate response from the options provided would be:
"I understand you're concerned. Let's discuss what concerns you specifically."
This answer demonstrates an empathetic and professional approach, showing a willingness to listen and address specific worries the parents may have. It fosters an environment where open communication can take place, which is crucial in healthcare settings and specifically in pediatric nursing.