可以用于判断两种商品或者服务是否具有替代关系或互补关系的指标是()。

A.需求价格弹性 

B.需求交叉弹性 

C.供给价格弹性 

D.需求收入弹性

-_____ you _____ free tomorrow?

-No. I _____ free the day after tomorrow.[ ]

A. Are; going  to; will

B. Are; going to be; will

C. Are; going to; will be

D. Are; going to be; will be