Conversion of milk to curd improves its nutritional value by increasing the amount of:

Options

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

Explanation

To solve the question regarding the conversion of milk to curd and its impact on nutritional value, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Process**:
- When milk is converted into curd, it undergoes a fermentation process primarily due to the action of lactic acid bacteria, specifically Lactobacillus.

2. **Identifying Nutritional Changes**:
- This fermentation process not only thickens the milk but also alters its nutritional profile. We need to determine which vitamins are increased during this conversion.

3. **Evaluating the Options**:
- The options provided are:
- A) Vitamin D
- B) Vitamin E
- C) Vitamin B12
- D) Vitamin A

4. **Analyzing Each Vitamin**:
- **Vitamin D**: While important for bone health, it is not significantly increased in curd.
- **Vitamin E**: This vitamin is an antioxidant but does not have a notable increase in curd.
- **Vitamin B12**: This vitamin is crucial for the formation of red blood cells and the proper functioning of the nervous system. It is known to be present in higher amounts in fermented dairy products like curd.
- **Vitamin A**: Important for vision and immune function, but its levels do not significantly increase in curd compared to milk.

5. **Conclusion**:
- Based on the analysis, the conversion of milk to curd significantly increases the amount of **Vitamin B12**. Therefore, the correct answer is **C) Vitamin B12**.

### Final Answer:
The conversion of milk to curd improves its nutritional value by increasing the amount of **Vitamin B12**.

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