Roger Corporation's relevant range of activity is 3500 units to 9500 units. When it produces and sells 6500 units, its average costs per unit are as follows: Average Cost per Unit Direct materials Direct labor Variable manufacturing overhead Fixed manufacturing overhead Fixed selling expense Fixed administrative expense Sales commissions Variable administrative expense $ 6.30 $ 3.50 $ 2.00 $ 3.30 $ 0.75 $ 0.65 $ 1.50 $ 1.00 The incremental manufacturing cost that the company will incur if it increases production from 8500 to 8501 units is closest to: O $15.10 $11.80 O $15.85 O $19.00