单选题：assume that a system has 5 processes, their arrival time, length
assume that a system has 5 processes, their arrival time, length of the CPU-burst time, and priorities (small number implying a smaller priority) are listed below:
```
Process Arrival time Burst time Priority
P1 1 10 3
P2 2 20 1
P3 3 3 4
P4 4 7 3
P5 5 12 2
```
If the scheduler users round-robin scheduling algorithm ( with time slice of 2), which process will gain the longest waiting time? @[B](1)
A. P1
B. P2
C. P3
D. P4
E. P5
A.P1
B.P2
C.P3
D.P4
E.P5
答案：B
```
Process Arrival time Burst time Priority
P1 1 10 3
P2 2 20 1
P3 3 3 4
P4 4 7 3
P5 5 12 2
```
If the scheduler users round-robin scheduling algorithm ( with time slice of 2), which process will gain the longest waiting time? @[B](1)
A. P1
B. P2
C. P3
D. P4
E. P5
A.P1
B.P2
C.P3
D.P4
E.P5
答案：B