Assertion : Ignition temperature is the minimum temperature at which a substance catches fire.
Reason : All substances catch fire at same temperature.

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

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: "Ignition temperature is the minimum temperature at which a substance catches fire."
- This statement is **true**. Ignition temperature is indeed defined as the lowest temperature at which a substance will ignite and start to burn.

2. **Understanding the Reason**:
- The reason states: "All substances catch fire at the same temperature."
- This statement is **false**. Different substances have different ignition temperatures. For example, paper ignites at a lower temperature than wood or gasoline.

3. **Evaluating the Relationship**:
- The assertion is true, but the reason is false. The reason does not correctly explain the assertion because it incorrectly generalizes that all substances ignite at the same temperature.

4. **Conclusion**:
- Since the assertion is true and the reason is false, the correct conclusion is that the assertion is true, but the reason is not a correct explanation for the assertion.

### Final Answer:
- The correct answer is: **Assertion is True, Reason is False**.