How Is It Possible That the Moon Might Have Some

How is it possible that the Moon might have some water ice today?

A) Ice brought by comet impacts may be frozen in craters near the Moon's poles.
B) Ice is continually supplied to the Moon by impacts,and some of this ice will therefore be found almost anywhere on the Moon at all times.
C) Some cold regions of the Moon may still have ice that originally formed from the condensation of water released by outgassing.
D) The Moon has significant amounts of water bonded in its surface rock,so some of this water is frozen as ice.