汉译英：“到货地点、启运口岸、到达口岸”。( )

A．place of despatch; place of arrival; port of destination

B．place of arrival; place of despatch; port of destination

C．place of arrival; port of destination; place of despatch

D．port of destination; place of despatch; place of arrival

变量依据其在研究中（）的可以分为三种：自变量、因变量和无关变量。

A.程度

B.地位

C.内容

D.方法