Concept:The tangential force that opposes the sliding of an object on a surface is called friction.
Explanation:Friction acts along the boundary between two surfaces in contact.
It resists the relative motion or tendency of an object to slide freely.
This force is parallel to the surface, hence it is tangential.
Normal force acts perpendicularly to the surface, not along it.
Weight acts vertically downward due to gravity.
Upthrust is an upward force exerted by a fluid.
Thus, the tangential force that prevents free sliding is the frictional force.
Answer:B. Friction force