12. A manufacturing company produces a product. Over the year, they will need to purchase 18,000 units of a specialized component at a cost of $60 each. It costs $150 to make a purchase. As well, the relevant carrying costs (material handling, shrinkage, etc) cost is $6 per unit per year. The company requires a 15% annual rate of return on investment. How many units should they order at a time? A. 600 units B. 667 units C. 800 units D. 933 units E. 967 units