.— Was it there ____you were away to answer the phone?

—There is no doubt about it.

A．that

B．which

C．while

D．where

GSM phase 2+的增强多级优先和强占业务（eMLPP）最多可提供7个优先级别（A、B、0~4）。在签约时业务提供者根据用户的需要为用户设置一个优先级；在MSC侧定义组呼参考的时候，也给组呼参考定义1个优先级别。