Niacin is a vitamin present in

Options

A. NAD
B. NADP
C. FAD
D. 1 & 2

Answer

### Step-by-Step Solution:

1. **Understanding Niacin**: Niacin, also known as vitamin B3, is a vital nutrient that plays a crucial role in energy metabolism. It is essential for converting food into energy and maintaining the health of the nervous system, digestive system, and skin.

2. **Identifying Active Forms of Niacin**: The active forms of niacin are important to note. They include:
- **NAD (Nicotinamide Adenine Dinucleotide)**: This coenzyme is involved in redox reactions and is crucial for cellular respiration.
- **NADP (Nicotinamide Adenine Dinucleotide Phosphate)**: This is the phosphorylated form of NAD and is involved in anabolic reactions, such as fatty acid synthesis.

3. **Evaluating the Options**: The question provides several options regarding where niacin is present. Based on the understanding of niacin's role and its active forms:
- **Option 1 (NAD)**: Correct, as NAD is one of the active forms of niacin.
- **Option 2 (NADP)**: Correct, as NADP is another active form of niacin.
- **Option 3 (SAD)**: Incorrect, as SAD does not relate to niacin or its active forms.

4. **Conclusion**: The correct answer to the question "Niacin is a vitamin present in" is both NAD and NADP, which are the active forms of niacin.

### Final Answer:
Niacin is a vitamin present in NAD and NADP.

---