I believe C is your answer (also, I am also using tht same exact program!)
Answer:
There are six kinds of forces that act on objects when they come into contact with one another: Normal force, applied force, frictional force, tension force, spring force and resisting force. These forces make objects change their motion or movement , the act of going from one place to another.
Pressing two objects together with more force Increase friction
John needs to see a physical therapist because he cannot walk very well.