DoCtors holD lAughtEr CliniCs ______.
A．to givE BEttEr ConDition to thEir pAtiEnts
B．in orDEr to improvE pAtiEnts' hEAlth
C．to mAkE pAtiEnts smilE
D．to provE smilE AnD lAughtEr hAvE thE sAmE EFFECt