Click here for the Excel Data File a-1. Determine the optimal number of doughnut holes, in dozens, to stock if labor, materials, and overhead are estimated to be $3.40 per dozen, doughnut holes are sold for $5.00 per dozen, and leftover doughnut holes at the end of each day are sold the next day at half price. (Round your answer to the nearest whole number.) a-2. What is the resulting service level? (Round your answer to 2 decimal places.)