A : It is not possible to have constant velocity and variable acceleration.
R : Accelerated body cannot have constant velocity.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
C. If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statement, then mark (4).

Answer

To solve the assertion and reason question, we need to analyze both statements carefully.

### Step 1: Understand the Assertion
The assertion states: "It is not possible to have constant velocity and variable acceleration."

**Explanation**:
- Constant velocity means that the speed and direction of an object do not change over time.
- If the velocity is constant, the change in velocity is zero, which means acceleration (the rate of change of velocity) must also be zero.
- Therefore, if acceleration is variable, it implies that the velocity cannot remain constant.

### Step 2: Understand the Reason
The reason states: "Accelerated body cannot have constant velocity."

**Explanation**:
- An accelerated body is one that experiences a change in velocity.
- If an object is accelerating, it means its velocity is changing over time, which directly contradicts the idea of having a constant velocity.
- Thus, this statement is also true.

### Step 3: Determine the Relationship
Now, we need to determine if the reason correctly explains the assertion.
- Since both the assertion and reason are true, and the reason provides a valid explanation for the assertion, we conclude that the reason supports the assertion.

### Conclusion
Based on the analysis:
- Both the assertion and reason are true.
- The reason correctly explains the assertion.

### Final Answer
The correct option is **Option 1**: If both assertion and reason are true and the reason is the correct explanation of the assertion.

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