Erkkila Inc. reports that at an activity level of 2, 100 machine-hours in a month, its total variable inspection cost is $69, 846 and its total fixed inspection cost is $9, 072. What would be the total variable inspection cost at an activity level of 2, 400 machine-hours in a month? Assume that this level of activity is within the relevant range. A) $78, 918 B) $69, 846 C) $79, 824 D) $10, 368