Which of the best describes the movement of an object at rest if no outside forces act on it?

Note that by the law of inertia, it's the nature of objects to continually be in motion. For something to be still, there has to be a presence of a force.

They mention "no outside forces" so you know that a kid isn't kicking the object or a train is hitting it, or anything like that. Still, there are internal forces working, and I drew it out for you :) Hope this helps!

Two cars collide, lock bumpers and move together after the collision.this collision is known as perfectly inelastic collision.