Demand for an item is 18965 units per year. Each order placed costs $91. The annual carrying cost percentage per item in inventory is 21% each. The variable purchase cost is $2.50 per unit if less than 3000 units will be ordered, $2.40 from 3000 units upto (but not including 4000 units), and $2.30 for at least 4000 units. These are all-units discounts. Part a: 3 points What is the optimal order quantity Q* for the unit cost of $2.30? Please round to a whole number. Locally stored answer: Part b: 2 points Is this quantity realizable/feasible? Please answer 'Yes' or 'No'. Locally stored answer: Part c: 5 points What is the optimal realizable/feasible total annual cost at a unit cost of $2.30? Parte: 2 points Is this quantity realizable/feasible? Please answer 'Yes' or 'No'. Locally stored answer: Part d: 3 points What is the optimal order quantity Q* for the unit cost of $2.40? Please round to a whole number. Locally stored answer: Locally stored answer: