单选题：In “Multilevel Queue Fixed priority” scheduling algorithm, curre

In “Multilevel Queue Fixed priority” scheduling algorithm, current statistics of processes in each queue and their scheduling algorithms are shown below. In this algorithm, processes in the “first foreground” are scheduled first, then the “second foreground” and the “background”. In each queue, we use different scheduling technique, e.g., in the “first foreground”, RR is applied. Please answer question 15 and 16.
```
Process Burst time Arriving time Algorithm
1st Foreground P1 50 0.0 RR interval:20
P2 15 30.0 RR is non-preemptive)

2nd Foreground P4 40 0.0 SJF Preemptive
P5 10 120.0

Background P6 30 60.0 FCFS
P7 20 130.0
```
What is the average turnaround time?@[D](1)
A. 140
B. 114
C. 96
D. 81





A.140
B.114
C.96
D.81


答案：D