Final answer:
The statement is false; external forces can change the momentum of a body as described by Newton's second law, which states that the change in momentum is directly proportional to the external force applied. The correct option is B.
Step-by-step explanation:
The statement 'The momentum of a body cannot be changed by an outside influence (force).' is false. According to Newton's second law of motion, the rate of change of momentum of a body is directly proportional to the external force applied to the body and occurs in the direction of the applied force.
This means that an external force can indeed change the momentum of the body, either by changing its speed or its direction, or both.
To clarify, when a net external force is applied to a body, it results in an acceleration (a change in velocity), leading to a change in momentum. Since momentum is the product of mass and velocity, any change in velocity will result in a change in momentum.
Internal forces within a system, on the other hand, cannot change the total momentum of the system because they cancel each other out, but the external forces can and do result in changes to momentum.