Friction a. is slow but steady movement along a fault. b. happens when rock is weak and can slip smoothly, without creating shock waves. c. is the process by which faults release energy. d. is the force that resists sliding along a surface

option D

Explanation:

The correct answer is option D

The friction force is the force that holds back the surface from sliding. It acts in the opposite direction of the motion of the body.

It can be explained with an example,

when you throw a ball on the ground it stops automatically this is because of friction which is acting opposite to the ball.

Friction also has benefits like due to friction we can walk, run, etc.  

So, from the given option

The force that resists sliding is friction force.

a and b sometimes have a positive value