The correct answer is: C. Saturation
Saturation is a non-linearity caused by servomotors when the output signal reaches the maximum or minimum value. This can happen when the motor is trying to move too quickly or when it is trying to move against a large load. Saturation can cause the motor to lose control and stop moving.
Static friction is the force that resists the initial movement of two objects that are in contact. It is caused by the attraction between the molecules of the two objects. Static friction is always greater than kinetic friction, which is the force that resists the movement of two objects that are already in contact.
Backlash is the amount of play between two gears or other moving parts. It is caused by the tolerances in the manufacturing process and by the wear and tear on the parts. Backlash can cause the motor to move in small steps instead of smoothly.
None of the above is the correct answer.