AQ$2.$ Inventory Management $(12$ marks$)$

A retailer purchases a product from a supplier. The retailer sells $20,000$ units of this product annually. The cost of placing an order is $$100,$ and the annual carrying cost per unit is $$16.$ The supplier offers the retailer a quantity discount as follows:

$\backslash$table$[[$Order Quantity,Unit Price $($$$)],[1$ to $499,20],[500$ to $999,19],[1,000$ to $1,999,c$