Although the rates are high in comparison with other modes of transport, the savings in insurance and packing costs help to______this.

A．compensate for

B．ward off

C．interfere with

D．ensue from

下列各项中不属于存货经济进货批量基本模式假设条件的是（）。

A.不存在数量折扣

B.存货的耗用是均衡的

C.仓储条件不受限制

D.可能出现缺货的情况