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 $5.60 per dozen, doughnut holes are sold for $7.20 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.) \begin{tabular}{|c|c|} \hline Demand(dozens) & Relative Frequency \\ \hline 19 & 0.01 \\ \hline 20 & 0.11 \\ \hline 21 & 0.12 \\ \hline 22 & 0.02 \\ \hline 23 & 0.14 \\ \hline 24 & 0.20 \\ \hline 25 & 0.12 \\ \hline 26 & 0.13 \\ \hline 27 & 0.09 \\ \hline 28 & 0.05 \\ \hline 29 & 0.01 \\ \hline \end{tabular}