Each select has the option of A,B,C,D, - . I would like an explaination of the though process when going through it also.

We have four jobs as follows: ob Arrival time CPU Burst Length 4 0 4 4 Assuming that the Round Robin (RR) scheduling policy with a quantum size of 3 units is used to schedule job CPU bursts, choose the job that will be scheduled in each of the time slot starting at each of the times indicated in the table below. If no job is scheduled in a given time slot, choose"-" Conventions: 1. If a job finishes before the end of its quantum, finish that quantum and begin a new one immediately 2. If a job finishes its quantum at the same time as a new job (i.e., a new CPU burst fora job) arrives, place the job that just finished its quantum ahead of the newly arriving job in the job queue. o [Select ] 1 Select ] 2 [Select] 3 [Select] 4[Select] 5 [Select] 6 [Select] 7 [Select] 8 [Select] 9 [Select] 10Select ] 11 Select ] 12 Select ] 13 Select ] 14 Select ] 15 Select ]