Chastain Company accumulated the following data concerning a mixed cost using miles as the activity level. January: 40,000 miles; total cost-$114, 200 February: 50,000 miles: total cost-$ 134,000 March: 70,000 miles; total cost-$181, 100 April: 60,000 miles; total cost-$161,000 Using the high-low method, what is the unit variable cost? $1.91 per mile $2.04 per mile $2.23 per mile $1.61 per mile