Answer
Graph B represents situations 2 and 3.
Work Step by Step
Graph B shows an accelerating velocity in the positive x-direction. To create and acceleration, there must be unequal forces acting upon an object. Situations 2 and 3 both have a force acting towards the right, that's greater than the force to the left. These unequal forces in situations 2 and 3 cause them to accelerate positively in the x direction.