Which Observation Has Been Made About the Moon That Will

Which observation has been made about the Moon that will be very helpful (if they prove true) as humans begin to plan for its colonization?

A) the discovery of evidence of water (as ice) that can be used for the support of life, the growth of food, and as fuel if it is split into hydrogen and oxygen by sunlight
B) its synchronous rotation, keeping one side opposite Earth at all times, simplifying communication with Earth stations
C) the mapping of rilles that, as collapsed lava tunnels, indicate that intact tunnels may be found that will be useful as shelter for early settlers
D) the discovery of coal, an essential source of fuel, in various locations