in 1970，iF 5 pErCEnt oF thE wAtEr usE wAs For DomEstiC purposEs．ApproximAtEly whAt wAs thE DAily AvErAgE numBEr oF gAllons oF wAtEr usED pEr CApitA For DomEstiC purposEs
A、105
B、50
C、20
D、10
E、5