Which of the following is not a coenzyme-

Options

A. NAD
B. NADP
C. FAD
D. ATP

Explanation

To determine which of the following is not a coenzyme, we need to understand the definitions and functions of the given options: NADP, NAD, FAD, and ATP.

### Step-by-Step Solution:

1. **Define Coenzymes**: Coenzymes are organic molecules that are non-protein in nature. They bind to the active site of enzymes and assist in catalyzing biochemical reactions. Without coenzymes, enzymes can be inactive.

2. **Identify the Options**: The options given are:
- NADP (Nicotinamide adenine dinucleotide phosphate)
- NAD (Nicotinamide adenine dinucleotide)
- FAD (Flavin adenine dinucleotide)
- ATP (Adenosine triphosphate)

3. **Analyze Each Option**:
- **NADP**: This is a coenzyme involved in redox reactions and helps in transferring electrons.
- **NAD**: Similar to NADP, it is also a coenzyme that plays a crucial role in metabolic processes, particularly in oxidation-reduction reactions.
- **FAD**: This is another coenzyme that participates in various biochemical reactions, especially in the Krebs cycle.
- **ATP**: While ATP is essential for energy transfer in cells, it is not classified as a coenzyme. Instead, it serves as the primary energy currency of the cell.

4. **Conclusion**: Based on the definitions and functions, NADP, NAD, and FAD are all coenzymes, while ATP is not. Therefore, the correct answer to the question is ATP.

### Final Answer:
**ATP is not a coenzyme.**

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