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 1 week lead times; B and E have lead times of two weeks. Lot for lot (L4L) 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 inventories. We are scheduled to recieve 20 units of item E in week 2; there are no other scheduled receipts. construct simple and low level coded BOM (product structure tree) and indented and summarized part lists. If 20 units of A are required in week 8, use the low level coded bill of materials to find the necessary planes order releases for all components.