Furniture, Inc., estimates the following number of mattress sales for the first four months of 2021: January 22,000 February 30,800 March 28,600 April 35,200 Finished goods inventory at the end of December is 6,600 units. Target ending finished goods inventory is 20% of the next month's sales. How many mattresses need to be produced in January 2021? Select one: a. 28,460 mattresses b. 21,560 mattresses c. 15,400 mattresses d. 34,160 mattresses