A standing desk consists of a desktop, four legs, and two adjustment motors. Each leg fastens to the desktop with one fastener set. Each adjustment motor requires two fastener sets for attachment to the legs. Currently there is one order outstanding, to make 180 standing desks. There are 500 legs and 20 desktops in inventory. There are no other large items in inventory, and no scheduled receipts.

(a) Draw the product structure tree.

(b) Calculate the net requirements to fulfill the outstanding order