A worker pushes a box across the floor to the right at a constant speed with a force of 25N. What can you conclude about the box?
A. An unbalanced force of 25N is acting on the box.
B. The net horizontal force acting on the box is 50N.
C. Friction between the box and the floor is 25N to the left.
D. Friction between the box and the floor is 25N to the right.