Friction can be reduced by changing from
A. Rolling to sliding
B. Sliding to rolling
C. Dynamic to staticD. Potential energy to kinetic energy

Friction: It is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact.
There are several methods to reduce friction i.e. the use of bearing surfaces that are themselves sacrificial, such as low shear materials, of which lead/copper journal bearings are an example. We can also replace sliding friction with rolling element friction, such as with the use of rolling element bearings.