During 24 hours there is a time when plants neither give `O_2` nor `CO_2`. This is the time of

Options

A. Night
B. Daylight
C. Twilight
D. None of these

Explanation

To solve the question, "During 24 hours there is a time when plants neither give O₂ nor CO₂. This is the time of," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Processes**:
- Plants perform photosynthesis during the day, which produces oxygen (O₂) and consumes carbon dioxide (CO₂).
- At night, plants undergo respiration, which consumes oxygen (O₂) and produces carbon dioxide (CO₂).

2. **Identify the Time Periods**:
- **Daylight**: During this time, photosynthesis occurs, and plants release oxygen.
- **Night**: During this time, respiration occurs, and plants take in oxygen and release carbon dioxide.
- **Twilight**: This is the transitional period between day and night.

3. **Analyze Twilight**:
- During twilight, the rate of photosynthesis decreases as light fades, and the rate of respiration starts to increase.
- At a certain point during twilight, the rate of photosynthesis can equal the rate of respiration. This is the critical moment when the net exchange of gases is zero, meaning plants neither release oxygen nor take in carbon dioxide.

4. **Conclusion**:
- The time when plants neither give off oxygen nor carbon dioxide is during **twilight**.

Thus, the correct answer is **twilight**.