M4_IND3. A supply chain consists of three plants (A, B, and C), three distributors (), K, and L), and three stores (X, Y, and Z). The relevant supply, demand, and unit shipping costs are given in the tables below. DEMAND (units) SUPPLY (units) 400 PLANT STORES A 450 600 450 350 350 The unit transportation costs (S) for the shipments from the plants to the distributors and from the distributors to the stores are shown below: TO DISTRIBUTOR K $5 $7 $8 $6 $4 $7 A FROM PLANT $8 $5 $6 TO STORE $6 $5 $8 $2 $8 FROM $5 $6 $7 $9 K DISTRIBUTOR Formulate this problem in Excel and solve to determine the minimum shipping costs required to meet demands. a) What is the total cost to minimize shipping costs from the plants? b) Which routes had zero units shipped? c) Which supplier did not ship out all of its supply? d) How many units should be shipped from C to ? e) How many units should be from K to Y?