Which of the following activities will lead to both air and water pollution?

Options

A. Use of manures and fertilisers in a crop field
B. Use of cooling devices like air conditioners and refrigerators
C. Burning of fossil fuels and use of fuel operated transport vehicles.
D. All of these

Answer

To determine which activity leads to both air and water pollution, let's analyze the options provided step by step.

### Step-by-Step Solution:

1. **Option A: Use of manures and fertilizers in a crop field**
- Manures and fertilizers are organic substances. They are generally considered safe for the soil and do not release harmful pollutants into the air or water.
- **Conclusion**: This option does not lead to air and water pollution.

2. **Option B: Use of cooling devices like air conditioners and refrigerators**
- Air conditioners and refrigerators can contribute to air pollution through the release of refrigerants and energy consumption, which may involve fossil fuels. However, they do not directly cause water pollution.
- **Conclusion**: This option does not lead to both air and water pollution.

3. **Option C: Burning of fossil fuels and use of fuel-operated transport vehicles**
- Burning fossil fuels (like petrol and diesel) releases harmful gases such as carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NO), and sulfur dioxide (SO2) into the atmosphere, causing air pollution.
- These gases can lead to acid rain, which results from the gases combining with moisture in the atmosphere. Acid rain can contaminate water bodies, leading to water pollution.
- **Conclusion**: This option leads to both air and water pollution.

4. **Option D: Not specified in the transcript**
- Since we do not have information on this option, we cannot evaluate it. However, based on the analysis of the other options, we have already identified option C as the correct answer.

### Final Answer:
The activity that leads to both air and water pollution is **C: Burning of fossil fuels and use of fuel-operated transport vehicles**.

---