whEn Do thE stuDEnts pAy For thE mEAls thEy ContrACt For
A．whEn thEy gEt thE mEAl.
B．At thE BEginning oF thE wEEk.
C．At thE BEginning oF thE yEAr.
D．At thE EnD oF thE yEAr.