20. The HRZ Company maintains a perpetual inventory system. Clerks in the accounting department post the data manually from receiving reports, materials requisition forms, copies of purchase orders, and other transactions, such as returns and adjustments to the inventory records. The source documents are filed by posting date. The inventory records are analyzed after each posting to determine if the item should be reor- dered. If an item needs to be reordered, a purchase requisition (one copy) is prepared and sent to the purchasing department. There, clerks select a vendor from a master vendor file, pre- pare a purchase order (four copies), and update the vendor file to reflect the order. The purchase order is approved and distributed as follows: original copy to the vendor; Copy 2 is filed numerically with the corresponding purchase requisition attached; Copy 3 is forwarded to the receiving department; Copy 4 is sent to the accounting department. Required a. Prepare an analytic flowchart of the preceding proce- dures. b. Prepare a DFD of the preceding procedures