Assertion : A lift is ascending with decreasing speed means acceleration of lift is downwards.
Reason : A body always moves in the direction of its acceleration.

Options

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

Explanation

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

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "A lift is ascending with decreasing speed means acceleration of the lift is downwards."
- When a lift ascends but its speed is decreasing, it implies that the lift is moving upwards but is experiencing a net force acting downwards. This is because the lift is not able to maintain its speed against the force of gravity, which is acting downwards.

2. **Analyzing the Motion**:
- In physics, when an object is moving upwards and its speed is decreasing, it is undergoing negative acceleration (or deceleration). This means that the acceleration vector is directed opposite to the velocity vector.
- Since the lift is moving upwards (positive direction), the acceleration must be directed downwards (negative direction) to cause the speed to decrease.

3. **Understanding the Reason**:
- The reason states that "A body always moves in the direction of its acceleration."
- This statement is not universally true. A body moves in the direction of its velocity, which can be different from the direction of its acceleration. For example, in the case of the lift, the lift is moving upwards (velocity upwards) while experiencing a downward acceleration.

4. **Conclusion**:
- The assertion is true because the lift is indeed ascending with decreasing speed, indicating that the acceleration is downward.
- The reason is false because it incorrectly states that a body always moves in the direction of its acceleration.

5. **Final Answer**:
- Since the assertion is true and the reason is false, the correct option is: **Assertion is true but reason is false.**