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
January	1,000		$	6,000
February	1,900		$	7,100
March	2,600		$	8,100
April	700		$	4,350

Using the high-low method, the estimated variable cost per machine hour for utilities is:

Multiple Choice

• $3.12.

• $4.12.

• $5.50.

• $1.97.

• $6.21.