$1.$ Product A is made of two units of B and two units of C$.$ B is made of three units of D and four E$.$ C is made of three units of F and two units of E$.$ Lead times for purchase of each unit are: A takes one week, B takes two weeks, C takes one week. D and E take $2$ weeks and F takes $3$ weeks. Assume that there is a demand for $75$ units of A in week $8.$ There is on$-$hand inventory of $30$ units of B$,$ and $20$ units of C$.$ There is a scheduled receipt of E for $500$ units in week three. Assume all items are purchased L$4$L except for item D which is ordered in multiples of $50,$ F which is ordered in multiples of $100$ and E which is $500$

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.