Assertion : Photochemical smog is produced by oxides of nitrogen.
Reason : Vehicular pollution is a major source of oxides of nitrogen.

Options

A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement
D. Assertion is wrong statement but reason is correct statement.

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Photochemical smog is produced by oxides of nitrogen."
- Photochemical smog is indeed a type of air pollution that occurs when sunlight reacts with nitrogen oxides (NOx) and volatile organic compounds (VOCs). This reaction produces a mixture of pollutants, including ozone, which contributes to the brown haze characteristic of photochemical smog.
- Therefore, the assertion is **true**.

2. **Understanding the Reason**:
- The reason states that "Vehicular pollution is a major source of oxides of nitrogen."
- It is well-established that vehicular emissions are a significant source of nitrogen oxides. Cars, trucks, and other vehicles release NOx as a byproduct of fuel combustion.
- Hence, the reason is also **true**.

3. **Evaluating the Relationship**:
- While both the assertion and the reason are true, we need to determine if the reason correctly explains the assertion.
- The assertion discusses the formation of photochemical smog, while the reason talks about the source of nitrogen oxides. The reason does not directly explain why photochemical smog is produced by nitrogen oxides; it merely states a fact about their source.
- Therefore, the reason is **not a correct explanation** for the assertion.

4. **Conclusion**:
- Since both the assertion and the reason are true, but the reason does not explain the assertion, the correct option is:
- "Assertion and reason both are correct statements but the reason is not the correct explanation for the assertion."

### Final Answer:
The correct option is: "Assertion and reason both are correct statements but the reason is not the correct explanation for the assertion."

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