A Piano Mover Raises a 100 Kg Piano at a Constant

Multiple Choice

A piano mover raises a 100 kg piano at a constant rate using a frictionless pulley system,as shown in the figure.With roughly what force is the mover pulling down on the rope?

A) 2000 N
B) 1000 N
C) 500 N
D) 250 N
E) Depends on the velocity!