Question

force c in the image above represents...
buoyant force
friction
gravity
spring (elastic) force

Explanation:

Force C acts parallel to the surface in the opposite direction of the intended motion of the box. Friction is a force that opposes relative motion between two surfaces in contact. Buoyant force acts in a fluid and is related to the displacement of fluid. Gravity acts vertically downwards. Spring (elastic) force is related to the compression or stretching of a spring. Since the box is on a surface and C opposes its motion, it is friction.

Answer:

friction