`ATP` synthesis during light reaction is

Options

A. Oxidative phosphorylation
B. Photolysis
C. Photophosphorylation
D. Phosphorylation

Answer

To answer the question regarding ATP synthesis during the light reaction, we will follow these steps:

### Step-by-Step Solution:

1. **Understanding the Light Reaction**:
- The light reaction of photosynthesis is the process where light energy is converted into chemical energy. This occurs in the chloroplasts of plant cells.

2. **Role of ATP in Photosynthesis**:
- During the light reaction, the energy from sunlight is used to synthesize ATP (adenosine triphosphate) from ADP (adenosine diphosphate) and inorganic phosphate (Pi).

3. **Identifying the Process**:
- The specific process by which ATP is synthesized in the presence of light is termed "photophosphorylation". This distinguishes it from other processes that synthesize ATP.

4. **Reviewing Other Options**:
- **Oxidative Phosphorylation**: This occurs in cellular respiration and involves the use of chemical energy, not light energy.
- **Photolysis**: This refers to the breakdown of molecules (like water) using light energy, not directly related to ATP synthesis.
- **Phosphorylation**: This is a general term for adding a phosphate group to a molecule, but it does not specify the light-dependent aspect.

5. **Conclusion**:
- The correct term for ATP synthesis during the light reaction is **photophosphorylation**.

### Final Answer:
The correct answer is **photophosphorylation** (Option 3).

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