At an activity level of 8,000 machine-hours in a month, a corporation's total variable maintenance cost is $219,600 and its total fixed maintenance cost is $450,844. What would be the total variable maintenance cost at an activity level of 8,100 machine-hours in a month? Assume that this level of activity is within the relevant range. O $673,189 $231,072 O $678,825 $222,345