Sphere X of mass 2 kg, moving with a speed of 10 m/s, collides head on with sphere Y of mass 4 kg, moving in the opposite direction with a speed of 10 m/s. Which statement best describes the magnitude of the impulse exerted by each sphere during the collision? (a) The impulse exerted by X on Y is 4 times the impulse exerted by Y on X. (b) The impulse exerted by X on Y is 2 times the impulse exerted by Y on X (c) The impulse exerted by X on Y is 2 /2 times the impulse exerted by Y on X (d) The impulse exerted by X on Y is equal to the impulse exerted by Y on X (e) It is not possible to compare impulses without knowing whether or not the collision is elastic