3) [5 marks] Four matches, in four different cities, would be held this coming Thursday in the national football league. Five referees, from five different locations, are available to judge the four matches. The distances, in km, that every referee needs to drive to reach each of the four cities are given in the following table. Assign exactly one referee for each match, such that the total distance covered by all referees is minimized. \begin{tabular}{|l|c|c|c|c|} \hline & City 1 & City 2 & City 3 & City 4 \\ \hline Referee 1 & 210 & 90 & 180 & 160 \\ \hline Referee 2 & 100 & 70 & 130 & 200 \\ \hline Referee 3 & 175 & 105 & 140 & 170 \\ \hline Referee 4 & 80 & 65 & 105 & 120 \\ \hline Referee 5 & 95 & 115 & 120 & 100 \\ \hline \end{tabular}