Assertion`:-` For a very small `angle theta` ,`sinthetaapproxtheta`.
Reason `:-`At very small angle, arc, subtends a right angle at the centre of arc.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertiion.
C. If Assertion is True but the Reason is False.
D. If both Assertion & Reason are False

Explanation

To solve the question, we need to analyze the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that for a very small angle \( \theta \), \( \sin \theta \approx \theta \). This is a well-known approximation in trigonometry, particularly useful in physics and engineering when dealing with small angles.

2. **Understanding the Reason**:
- The reason claims that at a very small angle, the arc subtends a right angle at the center of the arc. This statement is misleading. In fact, for small angles, the arc length is approximately equal to the angle in radians, but it does not imply that the arc subtends a right angle at the center.

3. **Graphical Representation**:
- If we plot the graph of \( y = \sin \theta \) and \( y = \theta \) (where \( \theta \) is in radians), we see that as \( \theta \) approaches 0, both curves converge. This graphical representation supports the assertion that for small angles, \( \sin \theta \) is approximately equal to \( \theta \).

4. **Conclusion**:
- The assertion is true because \( \sin \theta \approx \theta \) for small angles. However, the reason is false because it incorrectly describes the relationship between the angle and the arc. Thus, we conclude that the assertion is true, but the reason is false.

### Final Answer:
- Assertion: True
- Reason: False