Pick up the correct statement

Options

A. CO which is a major pollutant resulting from the combustion of fuels in automobiles plays a major role in photochemical smog.
B. Classical smog has an oxidizing character while the photochemical smog is reducing in character
C. Photochemical smog occurs in day time whereas the classical smog occurs in the morning hours
D. During formation of smog the level of ozone in the atmosphere goes down.

Explanation

To solve the question "Pick up the correct statement," let's analyze the statements provided in the video transcript step by step.

### Step 1: Analyze the First Statement
The first statement claims that carbon monoxide (CO) is a major pollutant resulting from the combustion of fuels in automobiles and plays a major role in photochemical smoke.

**Evaluation:**
- This statement is partially correct as CO is indeed a pollutant from automobile combustion. However, it does not play a major role in photochemical smoke; rather, it is ozone and other compounds that are significant in photochemical reactions.

### Step 2: Analyze the Second Statement
The second statement suggests that carbon monoxide smoke is oxidized while photochemical smoke is reduced.

**Evaluation:**
- This statement is incorrect. Carbon monoxide is typically considered a reducing agent, and photochemical reactions involve oxidation processes, particularly with ozone formation.

### Step 3: Analyze the Third Statement
The third statement mentions that carbon monoxide smoke is reduced during the daytime while it is reduced during morning hours.

**Evaluation:**
- This statement is misleading. Carbon monoxide does not have a specific reduction pattern that is limited to morning hours. CO levels can vary based on traffic and other factors throughout the day.

### Step 4: Conclusion
After analyzing all statements:
- The first statement is misleading.
- The second statement is incorrect.
- The third statement is also misleading.

However, based on the context provided, it seems that the intention was to highlight that photochemical reactions, which involve ozone, are more prominent during the day due to sunlight, and CO is a pollutant that can affect air quality.

### Final Answer
None of the statements are entirely correct as per the analysis. However, if we had to choose the one that aligns closest with environmental chemistry principles, it would be the first statement, as CO is indeed a pollutant from combustion, but it does not play a major role in photochemical smoke.

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