单项选择题
A.if(vip=="钻石会员"){sale=6;}else{if(vip=="白金会员"){sale=7}else{sale=8}else{sale=0}}
B.if(vip=="钻石会员"){sale=6;}elseif(vip=="白金会员"){if(vip=="黄金会员"){sale=8;}else{sale=0;}}
C.if(vip=="钻石会员"){sale=6;}elseif(vip=="白金会员"){sale=7;}elseif(vip=="黄金会员"){sale=8;}else{sale=0;}