According to the passage, the maria differ from the terrace mainly in terms of ______.

A．the possibility of finding water on the Moon
B．the lunar regolith
C．cataloging various land formations
D．craters and their origins

A．What astronomers learned from the Surveyor and Apollo space missions.
B．Characteristics of the major terrains of the Moon
C．The origin of the Moon's craters.
D．Techniques used to catalogue the Moon's land forms.