Three identical solid spheres moves down three incline planes A, B and C - all of the same dimensions. A is without friction, the friction between B and sphere is sufficient to cause rolling without slipping, the friction between C and sphere causes rolling with slipping. The kinetic energies on A, B and C at the bottom of the inclines are EA, EB and EC
In the absence of friction; no loss of energy takes place. When static friction acts on the sphere, there is no slipping between the sphere and the surface and no loss of energy occurs. So EA = EB = initial potential Energy. On the plane C, the sphere slips and frictional losses take place.
EC Initial potential energy. Hence, option - (2) is right.