a.?The purchasing manager is probably taking advantage of some large-volume quantity discounts offered by suppliers of lower-grade raw materials input items.  More items are being purchased than are needed for current period production.  Because raw material inventory quantities are increasing at a rapid rate, the carrying cost to Williamson, Inc., will soon get out of control.  Moreover, the inferior quality of these raw material inputs has led to consistently unfavorable usage variances, canceled purchase orders (lost sales), and unpleasant working conditions (unfavorable labor efficiency variances).