Detmer Enterprises has budgeted sales for the next five months as follows: January.......3,800 units February......6,800 units March.........5,400 units April...........7,200 units May............4,600 units Past experience has shown that the ending inventory for each month should be equal to 10% of the next month's sales in units. The inventory on December 31 contained 400 units, which was in excess of the desired level of inventory. The company needs to prepare a Production Budget for the first quarter of the year. The desired ending inventory for April is: a. 460 units b. 540 units c. 720 units d. 680 units