Assume a comet is traveling at a constant velocity in deep space. why would it speed up as it approaches our solar system?

a.) an object under no other outside influences naturally speeds up

b.) a comet's speed is influenced by the length and make-up of the tail it exhibits

c.) the solar system happens to be in the area of the comet's orbit where it normally speeds up

d.) the gravitational force fields of the sun and planets in the solar system accelerates it

explain when you answer.