Concept:A rock that can retain underground water must have spaces or pores to hold it.Explanation:Permeable rocks have tiny openings, cracks, or pore spaces that allow water to pass through and be stored.Such water-bearing rocks are commonly called aquifers.Crystalline and compact rocks are dense and do not easily hold water.Impermeable rocks prevent water from passing through them.Thus, the rock that can retain underground water is a permeable rock.Answer:C. permeable