Final answer:
The appropriate response when a family asks a nurse for reassurance about a client's condition is to understand their concerns and discuss them specifically.
Step-by-step explanation:
An appropriate response when a family asks a nurse for reassurance about a client's condition is D. "I understand you're concerned. Let's discuss what concerns you specifically." This response acknowledges the family's concerns and opens up a conversation to address their specific worries. It shows empathy and invites the family to share their thoughts and fears with the nurse.