B: An object will remain at rest or keep moving with a constant velocity unless a force acts on it
Example: lets say that you have a cotton ball and you place it on a table. it will not move because equal forces are acting on it. if you flick the cotton ball, it will move across the table because unequal forces are now acting on it. An object in motion stays in motion unless another force acts upon it causing it to stop. An object at rest stays at rest unless another unbalanced force acts upon it causing it to move.