Q4) (30p) Consider a lot sizing problem. (Lot sizing is determining which months to produce.) Demand for product in the following six months are; 10, 15, 5, 20, 30 and 25 . Assume holding cost of $3 per period and a production setup cost of $15. Formulate the problem as a shortest path problem and solve with Djikstra's Algorithm. (Hint: Use cij variable as cost of satisfying demand of periods >i and j with a production in period i+1. Ex: c02 means producing in the beginning of 1st month for the 1st and 2nd months' demands.)