throughout history golD ______.
A．hAs plAyED An importAnt rolE in thE worlD EConomy
B．hAs sEt thE stAnDArD By whiCh All othEr Forms oF monEy ArE vAluED
C．hAs Brought out thE worst in thE humAn ChArACtEr
D．hAs BEEn ExtrEmEly DiFFiCult to FinD