15A-12. Can someone show me how to do this problem?

Will rate a thumb up for good response thanks so much (PLEASE CIRCLE OR HIGHLIGHT final answer thx)

The Green Cab Company has a taxi waiting at each of four cabstands in Evanston, Illinois. Four customers have called and requested service. The distances, in miles, from the waiting taxis to the customers are given in the following table. Customer Cab Site A B C D 5 2 6 3 1 2 5 4 Stand 1 Stand 2 Stand 3 Stand 4 3 4 7 4 2 6 4 5 The optimal assignment of taxis to customers that minimizes the distance is: Customer A Customer B 1 1 1 1 Customer C Customer D The cumulative distance of the optimal assignment of taxis to customers = miles (enter your response as a whole number). Customer A Customer B ++++ Stand 1 Customer C Stand 2 Customer D D Stand 4 miles (enter your response as a whole nun Stand 3