PART A: Is asking for a network representation between customers &/or warehouses. Here's a reference of what it should look like:

3. Himsheys produces chocolates. The distribution system for the HisManCo consists of three plants, two warehouses, and four customers. Plant capacities and shipping costs per unit (in dollars) from each plant to each warehouse are as follows: Plant 1 can manufacture up to 560 chocolate bars at a cost of $17 per unit. Plant 2 can manufacture up to 480 chocolate bars at a cost of $18 per unit. Plant 3 can manufacture up to 390 chocolate bars at a cost of $20 per unit. Because of the long distance, the chocolate bars produced in Plant 1 cannot be shipped to Warehouse 2. Shipping costs per unit (in dollars) from each plant to each warehouse are as follows: Demand is 330 for Customer 1, 400 for Customer 2, 380 for Customer 3, and 320 for Customer 4. It is not possible to ship chocolate bars from Warehouse 2 to Customer 3. Shipping costs per unit (in dollars) from each warehouse to each customer are as follows: a) Develop a network representation of this problem. Solution: (a) The network representation of the problem is shown below