a$)$ Find the total transportation cost using Vogel's Approximation Method when the unit transportation costs, demands and supplies are as given below:

$\backslash$table$[[\backslash$table$[[$Destination$],[$Origins$]],$D$1,$D$2,$D$3,$D$4,$Supply$],[$O$1,6,1,9,3,70],[$O$2,11,5,2,8,55],[$O$3,10,12,4,7,70],[$Demand$,85,35,50,45,]]$