A 20-Kg Object Moves in a Straight Line on a Horizontal

Multiple Choice

A 2.0-kg object moves in a straight line on a horizontal frictionless surface.
The graph shows the velocity of the object as a function of time. The various equal time intervals are labeled using Roman numerals: I, II, III, IV, and V. The net force on the object always acts along the line of motion of the object.
-Which section(s) of the graph corresponds to a condition of zero net force?

A) V only
B) III only
C) II and IV
D) II, III, and IV
E) I, III, and V