The correct option is B Inertia of motion
Inertia of an object is the resistance to change its state. When the bus moves, the person inside moves along with the bus. The person is in a state of motion, but when they jump out and land on the ground, the lower half of their body comes to an abrupt stop. Due to the inertia of motion, the upper half of their body resists this sudden change in state and continues to move in the direction of the bus, causing the person to roll forward.