In completely inelastic collision

Options

A. The complete KE of the medium must lost
B. The linear momentum of the system must remain conserved during collision
C. Both (the complete KE of the medium must lost) and (the linear momentum of the system must remain conserved during collision) are correct
D. Both (the complete KE of the medium must lost) and (the linear momentum of the system must remain conserved during collision) are incorrect

Explanation

### Step-by-Step Solution:

1. **Understanding Completely Inelastic Collision**:
- In a completely inelastic collision, two objects collide and stick together after the collision. This means they move with a common velocity post-collision.

**Hint**: Remember that in a completely inelastic collision, the objects do not separate after colliding.

2. **Kinetic Energy Consideration**:
- In a completely inelastic collision, some kinetic energy is lost. However, it is incorrect to say that all kinetic energy is lost. The total kinetic energy before the collision is greater than the total kinetic energy after the collision.

**Hint**: Kinetic energy is not conserved in inelastic collisions, but it is not completely lost either.

3. **Conservation of Momentum**:
- The law of conservation of momentum states that the total momentum of a closed system before and after a collision remains constant. Therefore, in a completely inelastic collision, the total momentum before the collision equals the total momentum after the collision.

**Hint**: Always check if momentum is conserved in any type of collision.

4. **Evaluating the Options**:
- **Option 1**: "The complete kinetic energy of the medium must be lost." - This is incorrect because it misinterprets the term "medium" and incorrectly states that all kinetic energy is lost.
- **Option 2**: "The linear momentum of the system must remain conserved during the collision." - This is correct as momentum is conserved in all types of collisions.
- **Option 3**: "Both the complete kinetic energy of the medium must be lost and the linear momentum of the system must remain conserved during collision are correct." - This is incorrect due to the first part being wrong.
- **Option 4**: "Both the complete kinetic energy of the medium must be lost is wrong and the linear momentum of the system must remain conserved during collision are incorrect." - This is incorrect because momentum is conserved.

**Hint**: Analyze each statement carefully to determine if they align with the principles of physics regarding collisions.

5. **Conclusion**:
- The correct answer is **Option 2**: "The linear momentum of the system must remain conserved during the collision."

**Hint**: Always remember that momentum is conserved in all types of collisions, while kinetic energy may not be.