An orange is a fruit known for being a great source of vitamin C. Vitamin C, also called ascorbic acid, helps the body make collagen, supports normal immune function, and improves the absorption of iron from plant foods.
Orange flesh is mostly water and carbohydrates, with very little fat. A reference serving provides roughly 59 percent of the Daily Value for vitamin C, although the exact amount varies with the orange's size, variety, ripeness, and storage.
The fruit's reputation is deserved, but oranges are not the only foods rich in vitamin C. Guava, kiwi, strawberries, bell peppers, broccoli, and several other fruits and vegetables can provide as much or more. The other choices in this question—grape, banana, and apple—contain vitamin C in smaller amounts.
Whole oranges also provide fiber, especially when eaten rather than juiced. Juice supplies vitamin C but generally has less fiber and can be easier to consume quickly, so the whole fruit is often the more filling choice.