Simon Company's high and low level of activity last year was 60,000 units of product produced in May and 20,000 units produced in November. Machine maintenance costs were $78,000 in May and $30,000 in November. Using the high-low method, determine an estimate of total maintenance cost for a month in which production is expected to be 45,000 units. $67,500 $72,000 $58,500 $60,000