Sherman's inventory at the end of March was 900 units. Its budgeted sales for the upcoming quarter are as follows: April May June Units 1,800 2,000 1,700 The desired ending finished goods inventory for each month is one-half of next month's budgeted sales. Four pounds of direct material are required for each unit produced. If direct material costs $3 per pound, and must be paid for in the month of purchase, the budgeted direct materials purchases (in dollars) for April are: Select one: a. $21,600. b. $20,400. c. $22,800. d. $24,000