21. Maintenance costs at a Straiton Corporation factory are listed below: Machine- Hours Maintenan ce Cost March 3,627 April 3,588 $ 54,384 $ 53,980 $ 54,453 May 3,637 June 3,638 $ 54,491 July 3,572 $ 53,843 August 3,611 $ 54,196 September 3,644 $ 54,550 October 3,609 $ 54,181 November 3,669 $ 54,767 Management believes that maintenance cost is a mixed cost that depends on machine-hours. Use the high-low method to estimate the variable and fixed components of this cost. Compute the variable component first and round off to the nearest whole cent. Compute the fixed component second and round off to the nearest whole dollar. These estimates would be closest to: A) $0.10 per machine-hour; $54,382 per month B) $15.00 per machine-hour; $54,316 per month C) $9.12 per machine-hour; $21,309 per month D) $9.53 per machine-hour; $19,801 per month