If the following jobs are sequenced according to the SLACK rule then the mean completion time (in days) for all jobs is (assume zero for today’s date)Job Processing Time (days) Due DateA 8 12B 6 15C 11 17D 7 10E 3 8Select one:a. 35 daysb. 20.8 daysc. 18.4 daysd. none of the above