Final answer:
The nurse's most appropriate response is to explore the client's diet for more variety.
Step-by-step explanation:
The most appropriate response by the nurse is C) Let's look at your diet and see what type of variety we can find. It is important for a newly diagnosed client with diabetes mellitus to have a balanced and varied diet to ensure they are getting all the essential nutrients required for health. The nurse can work with the client to explore different food options within their prescribed diet to provide more variation and make the diet more enjoyable.