Night blindness is caused by deficiency of:

Options

A. Vitamin `B_(12)`
B. Vitamin A
C. Vitamin C
D. Vitamin E

Explanation

**Step-by-Step Solution:**

1. **Understanding Night Blindness:**
- Night blindness, also known as nyctalopia, is a condition where an individual has difficulty seeing in low light or darkness.

2. **Identifying the Vitamins:**
- The question asks which vitamin deficiency causes night blindness. We will analyze the options provided:
- **Option A: Vitamin B12**
- **Option B: Vitamin A**
- **Option C: Vitamin C**
- **Option D: Vitamin E**

3. **Analyzing Each Option:**
- **Vitamin B12:**
- This vitamin is primarily associated with the formation of red blood cells and the maintenance of the nervous system. Its deficiency leads to anemia but is not linked to night blindness.
- **Vitamin A:**
- Vitamin A, also known as retinol, is crucial for maintaining healthy vision, particularly in low light conditions. A deficiency in Vitamin A can lead to night blindness, as it is essential for the production of rhodopsin, a pigment in the retina that helps with vision in dim light.
- **Vitamin C:**
- This vitamin is important for immune function and skin health. Its deficiency leads to scurvy, which does not affect night vision.
- **Vitamin E:**
- Vitamin E is an antioxidant that protects cells from damage. Its deficiency can lead to nerve and muscle damage but does not cause night blindness.

4. **Conclusion:**
- Based on the analysis, the vitamin that causes night blindness when deficient is **Vitamin A**.

**Final Answer:**
Night blindness is caused by a deficiency of **Vitamin A**.

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