Answer:
Option d , speed over time - like running
Explanation:
Force is mathematical terms in defined as a product of mass of an object and it acceleration.
Acceleration is caused when speed changes over time.
Among all the given options, in option D the speed over time will cause acceleration and thus produce a force.
Force being a vector quantity required change of speed in some direction. While running , both quantity and direction can be assumed to be changing.
Thus, option D is correct.
