6 One unit of A is made of two units of B, three units of C, and two units of D. B is composed of one unit of E and two units of F. C is made of two units of F and one unit of D. E is made of two units of D. Items A, C, D, and F have one-week lead times; B and E have lead times of two weeks. Lot-for-lot (LAL) lot sizing is used for Items A, B, C, and D; lots of size 50 and 180 are used for Items E and F, respectively. Item C has an on-hand (beginning) inventory of 15; D has an on-hand inventory of 50; all other items have zero beginning inventory. We are scheduled to receive 20 units of Item E in Week 2; there are no other scheduled receipts. Construct simple and low-level-coded bills of materials (product structure tree) and indented and summarized parts list. If 20 units of A are required in Week 8, use the low-level-coded bill of materials to find the necessary planned order releases for all components. (See the note in Problem 5.)