阿兰索设计了( )来表示假设的地价和距离的组合。

A．区位平衡

B．贯价曲线

C．买价曲线

D．地价曲线

The external auditing shall be conducted by the Customs over the following enterprises and other organizations

A．Enterprises and other organizations engaged in foreign trade only

B．Enterprises and other organizations engaged in domestic trade only

C．Enterprises engaged in the business of inward process only

D．Both A and C