Final answer:
The LP/VN should inform the neighbor to check with the client's family because the LP/VN cannot share confidential patient information.
Step-by-step explanation:
The best response to make to the client's neighbor is option c: You will need to check with Mary's family; she is not on my unit. Patient health information is confidential and should not be shared without the patient's permission. As a healthcare professional, it is important to respect the privacy and confidentiality of patients. Therefore, it is not appropriate to share information about the client's health with a neighbor without the client's explicit consent.