Which vitamin deficiency is associated with night blindness?

Night blindness is primarily associated with a deficiency in vitamin A. Vitamin A plays a crucial role in maintaining healthy vision, particularly in low-light conditions. It is a component of rhodopsin, a protein in the retina that enables the eye to adapt to dark environments. When there is not enough vitamin A in the body, this can impair the ability to see in dim light, hence leading to night blindness, also known as nyctalopia.

The other vitamins listed are important for various bodily functions, but they are not directly linked to night blindness. Vitamin B is associated with energy metabolism and red blood cell production, vitamin C is vital for immune function and skin health, and vitamin D is important for bone health and calcium regulation. None of these play a direct role in the visual process related to night vision, which is specifically dependent on adequate levels of vitamin A.