The rope breaks and the box falls to the ground. Assume that air resistance on the box is negligible. During the fall, which of these statements are true: a) The work performed by all conservative forces on the box is 0. b) The work performed by all non-conservative forces on the box is 0. c) The net work performed on the box is 0. d) The work performed by all conservative forces on the box is positive. e) The work performed by all non-conservative forces on the box is positive