26. Consider the example presented in Section 8.2 of scheduling the production of the valve casing assembly. a. Suppose that the production capacity in any week is 100 valve casings. Using the algorithm presented in this section, determine the planned order release for the valve casings. b. What gross requirements schedule for the valves does the lot sizing you obtained in part (a) give? c. Suppose that the production capacity for the valves is 200 valves per week. Is the gross requirements schedule from part (b) feasible? If not, suggest a modification in the planned order release computed in part (a) that would result in a feasible gross requirements schedule for the valves. \begin{tabular}{lrrrrrrrrrr} \hline Week & 4 & 5 & 6 & 7 & 8 & 9 & 10 & 11 & 12 & 13 \\ Time-phased net requirements & 42 & 42 & 32 & 12 & 26 & 112 & 45 & 14 & 76 & 38 \\ \hline \end{tabular}