Assertion: For the plantes orbiting around the sun, angular speed, linear speed, K.E. changes with time, but angular momentum remains constant.
Reason: No torque is acting on the rotating planet. So its angular momentum is constant.

Options

A. Statement I is True, Statement II is True: Statement II is a correct explanation for Statement I.
B. Statement I is True, Statement II is True: Statement II is Not a correct explanation for Statement I.
C. Statement I is True, Statement II is False.
D. Statement I is False, Statement II is True.

Explanation

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

### Step 1: Understand the Assertion
The assertion states that for planets orbiting around the Sun, the angular speed, linear speed, and kinetic energy change with time, but the angular momentum remains constant.

- **Angular Speed (ω)**: This is the rate of rotation of the planet around the Sun. In elliptical orbits, this can vary.
- **Linear Speed (v)**: This is the speed at which the planet moves along its orbital path. This speed changes as the planet moves closer to or farther from the Sun.
- **Kinetic Energy (K.E.)**: This is given by the formula \( K.E. = \frac{1}{2}mv^2 \). Since linear speed changes, kinetic energy will also change.
- **Angular Momentum (L)**: This is given by \( L = mvr \), where \( r \) is the radius of the orbit. For a closed system with no external torque, angular momentum remains constant.

### Step 2: Understand the Reason
The reason states that no torque is acting on the rotating planet, which leads to the conclusion that its angular momentum is constant.

- **Torque (τ)**: Torque is the measure of the force that can cause an object to rotate about an axis. For a planet in orbit, the gravitational force acts as a centripetal force, and if there are no external forces causing a change in the rotational motion, the torque is zero.
- Since torque is zero, the change in angular momentum is also zero, confirming that angular momentum remains constant.

### Step 3: Conclusion
Both the assertion and the reason are true. The assertion correctly describes the behavior of the planets in orbit, and the reason accurately explains why the angular momentum remains constant.

### Final Answer
- **Assertion**: True
- **Reason**: True
- **Correct Option**: Statement 1 is true, Statement 2 is true, and Statement 2 is the correct explanation for Statement 1.