What is the primary function of vitamin C in the body?

Vitamin C, also known as ascorbic acid, plays a crucial role in boosting the immune system. It is a powerful antioxidant that helps protect immune cells from damage by free radicals and supports the function of various immune cells such as lymphocytes and phagocytes. By doing so, vitamin C helps the body resist infections and may reduce the duration and severity of colds.

Additionally, vitamin C is involved in the synthesis of collagen, a protein important for the health of skin, blood vessels, and connective tissues, which indirectly supports overall health and immune response. While vitamin C contributes to many processes in the body, its most prominent role is indeed in enhancing the immune response, making this the correct answer.