The buyer at Evans Enterprises purchases brackets for a high production item. The annual demand is $9000$ units. The following price structure was offered to the buyer: Purchase size: less than $250$ units $=$ $$36,250$ up to $999=$ $$32\mathrm{.}00,1000$ and over $=$ $$30\mathrm{.}00.$ The inventory carrying cost rate is $25\%$ and each purchase order costs $$80.$ What is the order quantity the buyer should choose?