Which of the following conditions are favourable for cyclic photophosphorylation

Options

A. Anaerobic condition and high `CO_(2)`
B. Aerobic and high `CO_(2)`
C. Aerobic and low light intensity
D. Anaerobic and low light intensity

Answer

### Step-by-Step Solution

1. **Understanding Cyclic Photophosphorylation**:
- Cyclic photophosphorylation is a process that occurs in photosynthesis, primarily involving Photosystem I (PSI). It is a non-cyclic form of photosynthesis that generates ATP without producing oxygen.

2. **Identifying the Key Components**:
- The process primarily involves the pigment P700, which is part of Photosystem I. When light is absorbed by P700, it energizes electrons that are then transferred through an electron transport chain (ETC).

3. **Conditions Favorable for Cyclic Photophosphorylation**:
- Cyclic photophosphorylation is favored under specific conditions:
- **Anaerobic Conditions**: This means that the process can occur without the presence of oxygen. In cyclic photophosphorylation, oxygen is not produced as a byproduct.
- **Low Light Intensity**: Under low light conditions, the plant can still generate ATP through this cyclic process, even if the overall rate of photosynthesis is reduced.

4. **Conclusion**:
- Based on the explanation, the conditions favorable for cyclic photophosphorylation are anaerobic conditions and low light intensity. Therefore, the correct answer is option 4.