What factors are considered to determine if something is moving?

An object is in motion if its distance relative to another object is changing. To tell if an object is moving, you use a reference point. If an object's distance from another object [reference point] is changing. A place or object used for comparison to determine if something is in motion.

I'm not too sure if this is what you needed go know, I hope it helped

The answer is b. hope this !