1. Electrical costs at one of Gotch Corporation's factories are listed below: Machine Hours Electrical Cost March 3,731 $35,243 April .. 3,728 35,248 May ... 3,765 35,479 June ... 3,793 35,651 July 3,797 35,692 August ... 3,701 35,044 September .. 3,800 35,694 October .. 3,735 35,276 November .. 3,740 35,325 Management believes that electrical cost is a mixed cost that depends on machine-hours. Using the high-low method to estimate the variable and fixed components of this cost, these estimates would be closest to: a. $0.15 per machine-hour; $35,115 per month b. $9.11 per machine-hour; $1,249 per month c. $9.43 per machine-hour; $35,406 per month d. $6.57 per machine-hour; $10,728 per month