Budgeted sales of the East End Burger Joint for the first quarter of the year are as follows:January ......................................................... $50,000February......................................................... 60,000March........................................................... 68,000 The cost of sales averages 40 percent of sales revenue and management desires ending inventories equal to 25 percent of the following months sales. Assuming the January 1 inventory is $5,000, the January purchases budget is: b. $21,000