Where in the Universe Would You Look for a Rille

Where in the universe would you look for a rille?

A) on Mars because rilles are the "canals" seen by Lowell to extend across the planet surface
B) in the galactic plane because it is a dark dust band
C) in Saturn's rings because rilles are the gaps in the rings
D) on the Moon because it is the name given to a deep winding canyon there