whiCh oF thE Following is truE
A．A pAin CAn only BE CAusED By physiCAl hArm.
B．somE pEoplE ArE ComplAining oF A pAin whiCh DoEs not Exist.
C．A pAin CAn BE CAusED By psyChogEniC FACtors.
D．EDuCAtED pEoplE Do not ComplAin oF nonExistEnt pAin.