please provide a netform network diagram and LP model

41 A mctal casting company can purchase its coal needs over three time periods from either of two suppliers, Because prices of the suppliers vary from period to period, the company may find it advantageous to buy more coal than it needs in a given period, and store the unused amount for later use. The cost of coal from the two suppliers, and maximum annount that can be purchased from cach, are shown in the following table. Cost of Coal/ton (5) Maximum No. of Tons Available Peno 1 Penod 2 Period Periodi Period 2 Period 3 Supplier 1 Supplter 2 900 1200 1301) 1900 1000 1200 70 90 KO 70 60 80 Finally, assume the company requires 130 tons in Perind 1, 120 tons in Period 2, and 150 tons in Period 3. with a required coding inventory or 5 tons (exactly) a. Provide 1 network diagram for the problem as stated for the objective of minimizing cost)