What is one of the main functions of vitamin A in the body?

Vitamin A plays a crucial role in maintaining surface epithelium and visual pigments within the body. This vitamin is essential for the health of epithelial tissues, which are found throughout the body, including the skin and lining of the respiratory, gastrointestinal, and urinary tracts. It stimulates the production and differentiation of epithelial cells, helping to ensure these tissues remain healthy and functional.

Additionally, vitamin A is vital for vision, particularly in the formation of rhodopsin, a visual pigment found in the retina. Rhodopsin is necessary for the eyes to detect light, allowing for proper functioning of night vision. Without adequate levels of vitamin A, night blindness and other vision-related issues can occur.

The other options, while they reflect important functions and benefits within the body, do not accurately capture the primary roles of vitamin A. Instead, they refer to functions associated with other nutrients or health processes. Thus, option B stands out as the correct choice regarding the main functions of vitamin A.