B is your answer hope this helps
That is the best book that I ( have read )on that subject.
reason = because that event has already happend in past but its impact is still on present so it is past perfect..........
B. a star at the center of our solar system
Stopping distance is dependent on the initial Kinetic energy (KE), the higher KE, the greater distance needed to stop. Because kinetic energy is equal to one half the total of mass times velocity squared (KE=1/2mv^2), if a large car with greater mass is traveling at the same speed as a small car with less mass, then the large car will have a greater initial KE and therefore requires greater distance to stop than the small car with less KE.
