3. Austin Medical Instruments has collected the following production data for the past four months: Units produced Total cost 2,000 10,000 5,000 19,000 1,500 8,500 3,000 13,000 If the high-low method is used, what is the estimated cost for producing 7,500 units in a particular month? a. $18,000. c. $18,500. d. $17,500. b. $26,500.