15. Use a spreadsheet program to develop the MRP records for parts A and B from the following product structure. Use the data from the following table: Part A B Requirements Initial inventory balance Lead time Lot size Safety stock Scheduled receipt 50/period 63 1 lot-for-lot 10 8 1 250 250 in period 1 A B (2 required) E (2 required) a. What are the planned orders for item B? b. On an unlucky day (it must have been the 13th), the planner for part A found that the inven- tory was wrong by 13 units. Instead of 63, there were only 55 on hand. What happens to the planned orders for part B? c. Use the spreadsheet model to generate a 10-period material plan for parts A and B. Assume that the 63 units of inventory for A were correct. Suppose that in period 1, actual demand for part A was 60 units instead of 50. Regenerate the spreadsheet for periods 2 through 11. What changes occur in the material plans for parts A and B