Midwest Electric transportation model

Midwest Electric has three electric power plants that supply the power needs of four cities. Each power plant has a maximum capacity for power generation. Plant $1$ can generate $35$ million kilowatt hours, Plant $2$ can generate $50$ million kilowatt hours, and Plant $3$ can generate $40$ million kilowatt hours. The peak power demand at each city must be met in order to serve Midwest's customers. The demand at the cities is as follows: $45$ kilowatt hours at City $1,20$ kilowatt hours at City $2,30$ kilowatt hours at City $3,$ and $30$ kilowatt hours at City $4.$ The cost of sending one million kilowatt hours from each plant to each city is given in the table below.

$\backslash$table$[[,$City $1,$City $2,$City $3,$City $4],[$Plar$,$$$8,$$$6,$$$10,$$$9$