Compare the length of a year on different planets to that of Earth.
Which of the following statements is true?
a) Planets closer to the Sun than Earth have a shorter year because their orbit is elliptical.
b) Planets farther from the Sun than Earth have longer years because they have a thinner atmosphere.
c) Planets closer to the Sun than Earth have shorter years because they have a shorter orbit around the Sun.
d) Planets farther from the Sun than Earth have shorter years because they spin on their axis more quickly.