The correct answer is: A. rolling to sliding.
Friction is a force that opposes the relative motion of two objects or materials. It is caused by the interaction of the microscopic surface features of the two objects. Friction can be reduced by changing the surface texture of the objects, by using lubricants, or by changing the shape of the objects.
When two objects slide against each other, the friction force is greater than when they roll against each other. This is because the contact area between two objects is greater when they slide than when they roll. The greater contact area results in more friction.
Therefore, friction can be reduced by changing from sliding to rolling. This can be done by using wheels, rollers, or bearings.
Option B is incorrect because sliding friction is greater than rolling friction.
Option C is incorrect because dynamic friction is less than static friction.
Option D is incorrect because potential energy is converted to kinetic energy when an object moves.