某台小型晚会由6个节目组成，演出顺序有如下要求：节目甲必须排在第四位、节目乙不能排在第一位，节目丙不能排在最后一位，该台晚会节目演出顺序的编排方案共有

A．36种

B．42种

C．48种

D．54种

The line of computing jobs waiting to be run on a computer system might be a （）.The jobs are serviced in the order of their arrival,that is ,the first in is the first out.

A．queue

B．stack

C．array

D．record