At an activity level of 5,400 units in a month, Zelinski Corporation's total variable maintenance and repair cost is $389,880 and its total fixed maintenance and repair cost is $118,800. What would be the total maintenance and repair cost, both fixed and variable, at an activity level of 5,600 units in a month? Assume that this level of activity is within the relevant range O $523,120 $527,52 $518,100 O $508,680