Assertion : Buffer stock is the extra stock of food grains which has to be maintained for emergency conditions.
Reason : For storage, extra moisture is removed by drying the food grains in the sun.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

### Step-by-Step Text Solution:

1. **Understanding the Assertion**: The assertion states that "Buffer stock is the extra stock of food grains which has to be maintained for emergency conditions." This means that buffer stock is a reserve of food grains set aside to ensure food security during times of shortage or crisis.

2. **Understanding the Reason**: The reason provided is "For storage, extra moisture is removed by drying the food grains in the sun." This explains a method of preparing food grains for long-term storage by reducing moisture content, which is essential to prevent spoilage.

3. **Analyzing the Assertion**: The assertion is correct because buffer stock is indeed maintained for emergencies. It helps to stabilize food supply in case of unforeseen circumstances like natural disasters or poor harvests.

4. **Analyzing the Reason**: The reason is also correct as drying food grains helps in preventing microbial growth, which can spoil the grains. However, while it explains a process related to the storage of food grains, it does not directly explain why buffer stock is maintained.

5. **Conclusion**: Both the assertion and the reason are correct statements. However, the reason does not adequately explain the assertion. Therefore, the correct option is that both the assertion and reason are correct, but the reason does not provide the correct explanation for the assertion.

### Final Answer:
Both the assertion and reason are correct, but the reason does not explain the assertion.

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