Vitamin `D` is called :

Options

A. Riboflavin
B. Ascorbic acid
C. Niacin
D. Calciferol

Answer

To answer the question "Vitamin D is called:", we will analyze the options provided and identify which one corresponds to Vitamin D.

### Step-by-Step Solution:

1. **Identify the Options**: The question likely provides four options, which we need to evaluate. Based on the transcript, the options include riboflavin, ascorbic acid, niacin, and calciferol.

2. **Analyze Each Option**:
- **Riboflavin**: This is known as Vitamin B2. Therefore, it does not correspond to Vitamin D.
- **Ascorbic Acid**: This is the name for Vitamin C, which is important for preventing scurvy. Hence, this is not Vitamin D.
- **Niacin**: This corresponds to Vitamin B3. Thus, it is also not related to Vitamin D.
- **Calciferol**: This is the correct term for Vitamin D. It is known to be a fat-soluble sterol.

3. **Conclusion**: Based on the analysis, we can conclude that Vitamin D is called calciferol.

4. **Final Answer**: The correct answer is that Vitamin D is called **calciferol**.