Consider the following transportation table for a minimization problem. Calculate the unit transportation cost of factory to warehouse for the given table.

	Warehouse 1	Warehouse 2	Warehouse 3	Warehouse 4	Supply
Factory 1	19 TL	11 TL	29 TL	20 TL	15
Factory 2	21 TL	16 TL	18 TL	29 TL	25
Factory 3	13 TL	23 TL	25 TL	27 TL	10
Demand	5	15	15	15

a. Draw the network diagram. (Write the related parameters on nodes and arcs)

b. Formulate the linear programming model to minimize the total transportation cost. (Write the decision variables, objective function and the constraints.)

c. Find a basic feasible solution for the given transportation problem using northwest corner method. Write the basic variables and their values clearly.

d. Find optimal solution by using stepping-stone method and the initial basic feasible solution you find in the previous question c. (For each iteration: Calculate improvement indices, write loops and total cost)

(please don't use software while solving this problem, thank you :)