Final answer:
The best referral for a client needing help with ADLs is Physical therapy, as it directly aims to improve their physical capabilities and independence in daily activities.
Step-by-step explanation:
A nurse caring for a client who requires assistance with Activities of Daily Living (ADLs) should recommend a referral to Physical therapy. Physical therapy can help improve the patient's ability to perform ADLs by strengthening their muscles, improving balance and coordination, and teaching them techniques to increase their independence. Whereas optometry, dentistry, and psychiatry may address specific health concerns, they do not directly assist patients in learning to perform ADLs.