I think it is A.. but then again im not sure
Answer:
Kinetic friction is an inhibitory force that is present when a body or object begins to move. It should be noted that this force is in the opposite direction to the movement of the body that slides with respect to a surface and parallel to that surface.
In addition, this friction varies according to the surface characteristics and the material properties of the bodies that slide in this surface. Being quantified by the coefficient of kinetic friction
, which is dimensionless.
One big application is the manufacture and use of mirrors.