University book store buys women's polo t-shirts from a supplier, which is $16 per unit. the store sells 50,000 t-shirts per year. the annual carrying cost of t-shirts is 25% of its purchasing price, and the ordering cost is $40. if the book store operates for 250 days each year, and delivery of an order takes 2 working days. how low can the inventory get before the book store places an order? group of answer choices 500 250 400 200