Assertion It is hotter over the top of a fire than at the same distance on the sides .
Reason In the upwared direction , the heat propagate through convection.

Options

A. Both assertion and reson are true and reason is the correct explanation of assertion
B. Both assetion and reason are true but reason is not the correct explanation of assertion
C. Assertion is true but reason is false
D. Both assetion and reason are flase

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 "It is hotter over the top of a fire than at the same distance on the sides."
- This is true because when a fire burns, it heats the air directly above it. The hot air is less dense and rises, leading to a higher temperature at the top compared to the sides.

2. **Understanding the Reason**:
- The reason states that "In the upward direction, the heat propagates through convection."
- This is also true. Convection is the process by which heat is transferred through a fluid (in this case, air) by the movement of the fluid itself. As the air above the fire heats up, it becomes lighter and rises, creating a convection current.

3. **Analyzing the Relationship**:
- While both the assertion and the reason are true, we need to determine if the reason correctly explains the assertion.
- The assertion is about the temperature difference above the fire compared to the sides, while the reason describes the mechanism (convection) that causes the hot air to rise.
- Therefore, while the reason is true, it does not directly explain why it is hotter above the fire compared to the sides at the same distance.

4. **Conclusion**:
- Since both statements are true but the reason does not provide a correct explanation for the assertion, we conclude that the assertion is true, the reason is true, but the reason is not the correct explanation for the assertion.

### Final Answer:
- The correct option is **B**: Assertion is true, Reason is true, but Reason is not the correct explanation of Assertion.