The Omega pharmaceutical firm has five salespersons, whom the firm wants to assign to five sales regions. Given their various previous contacts, the salespersons are able to cover the regions in different amounts of time. The amount of time (days) required by each salesperson to cover each city is shown in the following table:

Salesperson Region (days)
A B C D E
1 17 10 15 16 20
2 12 9 16 9 14
3 11 16 14 15 12
4 14 10 10 18 17
5 13 12 9 15 11

Which salesperson should be assigned to each region to minimize total time? Identify the optimal assignments and compute total minimum time.