Which of the following acid is a source of vitamin C? 

citric acid 

The correct answer is option 1. citric acid.

While citric acid itself is not vitamin C, it is commonly found in citrus fruits, which are excellent natural sources of vitamin C. Vitamin C, also known as ascorbic acid, is an essential nutrient that plays a crucial role in various bodily functions, including collagen formation, immune system support, and antioxidant protection.

Citric acid is present in various citrus fruits such as oranges, lemons, limes, and grapefruits. These fruits are valued not only for their citric acid content but also for their high vitamin C content. When you consume citrus fruits, the body metabolizes the vitamin C found in these fruits.

In summary:

Citric Acid: Found in citrus fruits, it adds a sour flavor and helps preserve the fruits. It is not vitamin C itself but is associated with fruits rich in vitamin C.

Vitamin C (Ascorbic Acid):  This essential vitamin is found in various fruits and vegetables, with citrus fruits being particularly well-known for their vitamin C content.

So, while citric acid is not the source of vitamin C, it is found in foods that are excellent sources of this essential nutrient.