Comets X and Y have the same semi-major axis about the Sun, but X has orbital eccentricity 0.2 while Y has eccentricity 0.8. Which statement compares their speed variation along the orbit?
(a) Neither comet changes its speed; conservation of angular momentum keeps the speed constant along the orbit.
(b) Comet X has the larger maximum-to-minimum speed ratio because its orbit is closer to circular (e=0.2).
(c) Comet Y has the larger maximum-to-minimum speed ratio because its orbit is more elongated (e=0.8).
(d) The maximum-to-minimum speed ratios of the two comets are equal since their semi-major axes are the same.