Assertion : 'Light year' and 'Wavelength' both measure distance.
Reason : Both have dimensions of time.

Options

A. if both assertion and reason are true reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation fo assertion.
C. If assertion is true but reaso 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 1: Analyze the Assertion**
- The assertion states that "Light year" and "Wavelength" both measure distance.
- A light year is defined as the distance that light travels in one year. This is indeed a measure of distance.
- Wavelength is the distance between successive peaks (or troughs) of a wave. This is also a measure of distance.
- Therefore, the assertion is **true**.

**Step 2: Analyze the Reason**
- The reason states that "Both have dimensions of time."
- The light year is a unit of distance (specifically, it is equivalent to about 9.46 trillion kilometers).
- Wavelength is also a unit of distance (measured in meters, nanometers, etc.).
- Neither light year nor wavelength has dimensions of time; they both have dimensions of length.
- Therefore, the reason is **false**.

**Step 3: Conclusion**
- Since the assertion is true and the reason is false, we conclude that the correct answer is that the assertion is true, but the reason is false.

### Final Answer:
Assertion is true, and Reason is false.