Which one of the following forces is a contact force?
The correct option is D Force of friction
Friction is a surface phenomenon. When two surfaces have irregularities that come in contact they get interlocked preventing them from sliding against each other. So, the frictional force is a contact force dependent on the surface.
Here, option (B) is correct.
Gravitational force, electrostatic force, and magnetic force do not depend on the surface.