Answer:
When the forces acting on an object have equal strength and act in opposite directions, they are balanced. These forces cancel out one another, and the motion of the object they are acting on remains unchanged. The object may change its speed (speed up or slow down), or it may change its direction.
So I think its C
You see this is because if the forces were different the object would either speed up or slow down but in this case the forces are equal so the motion of the object does not change.
Hope This Helps :)