The major source of CO pollution is:

Options

A. industrial processes
B. vehicular exhaust
C. forest fires
D. volcanic activity.

Answer

**Step-by-Step Solution:**

1. **Understanding Carbon Monoxide (CO):**
- Carbon monoxide is a colorless and odorless gas that can be harmful when inhaled in large quantities. It is important to recognize its properties and the dangers associated with it.

2. **Identifying Major Sources of CO Pollution:**
- The primary sources of carbon monoxide pollution are vehicles such as cars, trucks, and other machinery that burn fossil fuels.

3. **Understanding Vehicular Exhaust:**
- Vehicular exhaust refers to the gases emitted from the exhaust system of vehicles, specifically from the tailpipe. This exhaust contains burned gases and particulate matter produced by the engine during the combustion of fossil fuels.

4. **Conclusion:**
- Given the information, the major source of CO pollution is indeed the vehicular exhaust, which is a result of the combustion process in vehicles that burn fossil fuels.

5. **Correct Option:**
- Therefore, the correct answer to the question is "vehicular exhaust."

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