The following information is available for a company's cost of sales over the last five months. Month Units sold January 400 A February 800 Cost of sales 31,000 37,000 49,000 61,000 A March 1,600 A April 2,400 A Using the high-low method, the estimated variable cost of sales per unit sold is: O A. $15.00. O B. $30.62. O C. $34.23. O D. $25.42. O E. $77.50