Sailboats have pulleys that are used to raise and adjust the sails. The picture shows a wooden pulley commonly used on older sailboats.

However, the mechanical efficiency (ME) of this device is poor. Which action is most likely to increase the ME of the pulley system shown, and why?

A. Replace the wooden parts with plastic parts, because this would decrease friction that produces non-useful output work.

B. Replace the ropes with thick cables, because this would increase friction that produces non-useful output work.

C. Lengthen the ropes, because this would increase the distance over which input force can be applied to the pulley.

D. Shorten the ropes, because this would decrease the distance over which the pulley can apply output force.

A. is correct.​