唐朝后期，有不少粟特人迁往河北，对这种现象，你如何理解？

A、avoid reduction of the cell breathing and overloading the system
B、minimize the interference in the system
C、provide the continuous connection when moving among cells
D、transform original signal into another form that occupies a larger bandwidth

A、位移
B、车种
C、席别
D、查询服务