Fixation and reduction of `CO_(2)` require

Options

A. `ATP`
B. `NADPH`, chlorophyll, water
C. `ATP, NADPH`
D. `ATP, NADPH` and light.

Answer

To solve the question regarding what is required for the fixation and reduction of carbon dioxide (CO₂) during photosynthesis, we can analyze the options step by step.

### Step-by-step Solution:

1. **Understanding the Process**:
- The fixation and reduction of CO₂ occur during the Calvin cycle, which is a part of the dark reactions (light-independent reactions) of photosynthesis.

2. **Analyzing the Options**:
- **Option 1: ATP**
- ATP is indeed required for the Calvin cycle, but it is not the only molecule needed. Therefore, this option is incorrect.

- **Option 2: NADPH, Chlorophyll, or Water**
- While NADPH is required for the reduction of CO₂, chlorophyll and water are primarily involved in the light-dependent reactions. Thus, this option is also incorrect.

- **Option 3: ATP or NADPH**
- This option suggests that either ATP or NADPH is sufficient. However, both ATP and NADPH are essential for the fixation and reduction of CO₂, making this option misleading. Therefore, this option is incorrect.

- **Option 4: ATP, NADPH, and Light**
- This option includes ATP and NADPH, which are indeed required. However, light is not necessary for the fixation and reduction of CO₂ since these reactions can occur in the dark as well. Thus, this option is incorrect.

3. **Conclusion**:
- The fixation and reduction of CO₂ specifically require both ATP and NADPH, but not light. Therefore, the most accurate answer is that both ATP and NADPH are needed for the fixation and reduction of CO₂.

### Final Answer:
The fixation and reduction of CO₂ require ATP and NADPH.