A （） is a dedicated storage network that provides access to consolidated, block level storage. It is primarily used to make storage devices accessible to servers so that the devices appear as locally attached to the operating system.

A.network-attached storage

B.storage area network

C.direct attached storage

D.computer cluster

下列选项中属于三类有责投诉的有（）

A、对乘客有推、拉、打、踢等粗暴行为；

B、作弄、欺瞒乘客的行为；

C、车站公告栏的内容与实际运营不符；

D、票务中心中心人员找零不足，造成乘客投诉（除找零硬币不足的情况外