The primary electron acceptor in cyclic photo phosphorylation is

Options

A. A protein that contains iron and sulphur
B. Carbon dioxide
C. FAD
D. NADP

Answer

### Step-by-Step Solution:

1. **Understanding Cyclic Photophosphorylation**:
- Cyclic photophosphorylation is a process that occurs during the light-dependent reactions of photosynthesis. It involves the transfer of electrons in a cyclic manner.

2. **Identifying the Role of Light**:
- In this process, light energy is absorbed by chlorophyll, which excites electrons and initiates a chain reaction.

3. **Electron Transfer**:
- The excited electrons are transferred through a series of proteins and molecules in the thylakoid membrane, which includes Photosystem II (PSII).

4. **Primary Electron Acceptor**:
- In cyclic photophosphorylation, the primary electron acceptor is a specific protein that captures the excited electrons.

5. **Naming the Primary Electron Acceptor**:
- The primary electron acceptor in cyclic photophosphorylation is **ferredoxin**. Ferredoxin is a protein that contains iron and sulfur.

6. **Conclusion**:
- Therefore, the answer to the question is that the primary electron acceptor in cyclic photophosphorylation is **ferredoxin**.

### Final Answer:
The primary electron acceptor in cyclic photophosphorylation is **ferredoxin**.

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