A pottery manufacturer must "fire" the pottery pieces in an oven for 8 hours. The oven can hold 2,000 pieces of pottery. The worker monitoring the oven is paid an hourly wage. Which of the following would be considered a batch-level cost if a single piece of pottery is considered to be the "unit" of activity? A) The straight-line depreciation on the oven B) The cost of inspecting the finished pieces for cracks C) The employee's wages D) The glaze applied to the pottery pieces