McNeil uses the high-low method of estimating costs. McNeil had total costs of $56,500 at its lowest level of activity, when 4,500 units were sold. When, at its highest level of activity, sales equaled 9,500 units, total costs were $71,500. What would McNeil estimate its total cost to be if sales equaled 8,500 units? $25,500 $68,500 $99,500 $61,500