Consider the transportation table below. The solution displayed was obtained by performing some iterations of the transportation method on this problem. Source Denver Destination Yuma $8 Miami Supply $2. $1 Houston 25 25 $4 $5 $6 St. Louis 35 10 25 $6 $3 $2 Chicago 45 10 35 35 Demand 35 35 The total cost of the current solution provided = $ 315. Using stepping stone method, to perform an improvement iteration, the improvement index for the unused cell will be: Houston - Yuma = 5 Houston - Miami = -1 St. Louis - Miami = 2 Chicago - Denver = 4 Based on the improvement index for each of the unused cells, in the first improvement iteration, unused cell Houston - Miami should get an assignment of units