The following information is available for a company's utility cost for operating its machines over the last four months. Month Machine hours Utility cost $5,450 $6,900 $8,100 $3,600 January February 900 1,800 March 2,400 April 600 Using the high-low method, the estimated variable cost per machine hour for utilities is: $3.38. $6.00 $2.50 $4.22 $6.17