whAt DoEs thE worD "synAEsthEsiA" rEFErs to
A．it mEAns thAt pEoplE mAy ApprECiAtE two kinDs oF BEAuty At thE sAmE timE.
B．it mEAns thAt pEoplE mAy Enjoy BEAuty with All sEnsEs At thE sAmE timE.
C．it holDs thAt DiFFErEnt sphErEs oF sEnsEs mAy ovErlAp.
D．it is thoroughly stuDiED By moDEm sCiEnC