The correct answer is D. Be moving at a constant velocity.
Explanation:
According to Newton's first law of motion, which explains movement based on the forces that act on a body, an object would either remain at rest in the case this was its state or move at a constant velocity if the forces acting upon the object are balanced.
This can be explained as it is through unbalanced forces an object experiences either an increase in velocity (acceleration) or a decrease in velocity (deacceleration). For example friction between the object moving and the surface causes the object to slow down or experience deacceleration but without this, the object would keep moving at the same velocity. Thus, if the forces acting upon an object are balanced, then an object must be moving at a constant velocity.
