Final answer:
Grapes with skins would be the best source of fiber from the options provided, but it is essential to ensure a variety of fiber sources in the diet. The correct option is 1.
Step-by-step explanation:
When updating a meal plan for a client with resolving diverticulitis who is advancing to a high-fiber diet, the nurse should recognize that different foods provide varying amounts of dietary fiber. Among the options given, whole grains, legumes, vegetables, and fruits are excellent sources of dietary fiber, with vegetables and fruits being particularly important.
Comparing the provided options, grapes (with skins), which are higher in dietary fiber than the other options listed, would be a good source. However, it is essential to consider the entire diet to ensure a variety of fiber sources are included for overall gastrointestinal health.