4 Assume that Product Z is made of two units of A and four units of B. A is made of three units of C and four D. D is made of two units of E. Lead times for purchase or fabrication of each unit to final assembly are: Z takes two weeks; A, B, C, and D take one week each; and E takes three weeks. Fifty units are required in Period 10. (Assume that there is currently no inventory on hand of any of these items.)

a. Show the bill of materials (product structure tree).

b. Develop an MRP planning schedule showing gross and net requirements and order release and order receipt dates.