how DiD Dr. griFFiths DisCovEr thE gAmBlErs' FEElings whEn winning AnD losing
A．By ExAmining thE DiFFErEnt ChEmiCAls in gAmBlErs' BoDiEs.
B．By Asking thE gAmBlErs to spEAk AlouD thEir FEElings.
C．By Asking thE gAmBlErs to DisCuss thEir iDEAs.
D．By tEsting thE gAmBlErs' hEArt BEAt.