Consider the transportation table below. The solution displayed was obtained by performing some iterations of the transportation method on this problem.

Destination

Source

$1$

$2$

$3$

Capacity

Upper A

$$$$30$

$$$$30$

$$$$5$

$35$

$25$

$10$

Upper B

$$$$10$

$$$$10$

$$$$10$

$20$

$20$

Upper C

$$$$20$

$$$$10$

$$$$25$

$70$

$40$

$30$

Demand

$25$

$60$

$40$

Part $2$

The total cost of the current solution provided$=$

$$

$2150$ dollars.

Part $3$

Using stepping stone$$ method, to perform an improvement$$ iteration, the improvement index for the unused cell will$$ be:

Part $4$Part $5$Part $6$Part $7$

Upper Aminus$2$equals

$$

$40$

Upper Bminus$1$equals

$$

negative $40$

Upper Bminus$3$equals

$$

negative $15$

Upper Cminus$1$equals

$$

negative $30$

Part $8$

Based on the improvement index for each of the unused$$ cells, in the first improvement$$ iteration, unused cell Upper Bminus$1$ should get an assignment of

$$

enter your response here units.