Final answer:
To promote wound healing, the nurse should advise the client to eat oranges, as they are rich in vitamin C which is crucial for collagen synthesis and wound repair.
Step-by-step explanation:
The nurse should encourage the client to eat oranges, which are a food item that is naturally high in vitamin C to promote wound healing. Vitamin C plays a critical role in the synthesis of collagen, which is a vital component of the skin and essential for wound repair. Oranges, as compared to the other options like apples, chicken, and spinach, typically have a higher content of vitamin C.