Please explain part b in detailed simple terms regarding what the buyer should do and why. Thank you.

$4.$The following figures are rom a juniors$$ sportswear department in a California store for May: Markdowns $$42,000$ Purchases$($retail$)$ $$180,000$ Returns to Vendors $$3,500$ Transfers in from Oregon store $$8,000$ Transfers out to Arizona store $$4,000$ Net Sales $$125,000$ Opening Book Inventory$($retail$)$ $$315,000$ Determine the closing book inventory for May at Retail. If planned June book beginning inventory is supposed to be $$319,200,$ what does the buyer need to do$.$