Friction force acts opposite to the motion of body and acts parallel to the contact surface.

Option A  is correct.

Friction Between Two Bodies
Friction is a force that opposes the relative motion or tendency of such motion between two surfaces in contact. The force of friction can act in different directions depending on the orientation of the surfaces in contact. Let's explore the options provided:

a) Parallel
When the two bodies are in contact and moving parallel to each other, the frictional force between them is called parallel friction. This type of friction resists the motion of the bodies along the surfaces in contact.

b) Perpendicular
Perpendicular friction refers to the frictional force that acts perpendicular to the surfaces in contact. This type of friction occurs when one body is placed on top of another, and the force of friction acts in a direction perpendicular to the contact surfaces.

c) Inclined at 30 degrees
When the surfaces in contact are inclined at 30 degrees with respect to the horizontal plane, the frictional force between them will be a combination of both parallel and perpendicular components. The frictional force will act along the direction of the inclined plane and perpendicular to the normal force.

d) Inclined at 60 degrees
Similarly, when the surfaces are inclined at 60 degrees, the frictional force will have both parallel and perpendicular components. The direction and magnitude of the frictional force will depend on the angle of inclination and the normal force acting between the surfaces.
In conclusion, the force of friction between two bodies can vary in direction and magnitude depending on the orientation of the surfaces in contact. It is essential to consider the relative motion and the angle of inclination to understand the behavior of friction in different scenarios.