Rank Company is trying to decide how many units of merchandise to order each month. Company policy is to have $20\%$ of the next month's sales in inventory at the end of each month. Projected sales for August, September, and October are $45,000$ units, $38,000$ units, and $44,000$ units, respectively. How many units must be purchased in September?

$39,200.$

$38,000.$

$8,800.$

$30,400.$

$46,800$