Explanation:

- Night blindness is commonly caused by a deficiency of Vitamin A, which is crucial for maintaining good vision, especially in low-light conditions.

- Option 1, A: Correct answer. Vitamin A is essential for the production of rhodopsin, a pigment in the eyes necessary for seeing in dim light.

- Option 2, C: This vitamin is important for collagen synthesis and immune function, but not directly linked to night blindness.

- Option 3, K: Known for its role in blood clotting; not related to vision.

- Option 4, B12: Important for nerves and blood cells; not associated with night blindness.