Kesterson Corporation has provided the following information:

Cost per Unit Cost per Period Direct materials $ 7.10 Direct labor $ 4.10 Variable manufacturing overhead $ 1.50 Fixed manufacturing overhead $ 16,900 Sales commissions $ 2.00 Variable administrative expense $ 0.30 Fixed selling and administrative expense $ 3900 The incremental manufacturing cost that the company will incur if it increases production from 6500 to 6501 units is closest to: $12.70 $15.60 $18.20 $15.30