Allocation of jobs

There are seven people in isolation to get products and seven volunteers which can process any of those orders, with respective times $($in minutes$)$ as shown below. Determine the allocation of orders to the volunteers that will result in minimum delivery time.

$\backslash$table$[[$Order$,$Volunteer,$1,2,3,4,5,6,7],[$A$,,60,22,34,42,30,60,29],[$B$,,22,52,16,32,18,48,33],[C,,29,16,58,28,22,55,38],[D,,42,32,28,46,15,30,25],[E,,30,18,25,15,45,42,48],[F,,33,28,41,52,26,38,22],[$G$,,50,48,57,30,44,60,55]]$

If order $D$ for some reason should be delivered by volunteer $1,$ what deviation from minimum time will be then?

Hint. Look at the situation as a transportation problem, where all the capacities and demands are equal to $1.$