Which of the Following Statements Is an Example of Comparative

Which of the following statements is an example of comparative planetology?

A) Mercury should have more craters than Earth because it is closer to the Sun.
B) Geological features and the chemical composition of some rocks on Mars suggest liquid water flowed on the surface in the past, but not at the present time.
C) Venus should be cooler than Earth because it is smaller.
D) Jupiter's colored bands are evidence of tectonic activity.
E) The Moon has big, dark "seas," which are evidence of water having existed on its surface at one time.