If you were on the Moon and wanted to find a supply of water in some form, where would be the best place to get it?   a From ice in permanently-shadowed craters near the lunar poles.   b From the large bodies of water on the Moon's surface, such as the Sea of Tranquility.   c From underground water-bearing layers that were discovered by the Apollo landing missions.   d From large blocks of ice that have been found in craters along the Moon's equator.