Pernicious anaemia is caused by deficiency of vitamin

Options

A. `B_(1)`
B. `B_(12)`
C. C
D. D

Answer

**Step-by-Step Solution:**

1. **Understanding Pernicious Anemia**: Begin by recognizing that pernicious anemia is a type of anemia characterized by the inability of the body to absorb vitamin B12 effectively.

2. **Identifying Vitamin Deficiencies**: The question provides four options: B1, B12, C, and D. We need to analyze each vitamin's deficiency and its associated conditions.

3. **Analyzing Each Option**:
- **Vitamin B1**: A deficiency in vitamin B1 leads to beriberi, which is not related to pernicious anemia.
- **Vitamin B12**: A deficiency in vitamin B12 is directly linked to pernicious anemia. This condition is often caused by an autoimmune response that affects the production of intrinsic factor, a substance necessary for the absorption of vitamin B12 in the intestines.
- **Vitamin C**: Deficiency in vitamin C leads to scurvy, which does not relate to pernicious anemia.
- **Vitamin D**: A deficiency in vitamin D results in rickets, which is unrelated to pernicious anemia.

4. **Conclusion**: Based on the analysis, the correct answer is vitamin B12, as its deficiency is the direct cause of pernicious anemia.

**Final Answer**: Pernicious anemia is caused by a deficiency of vitamin B12.

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