You’re maybe getting confused by the inclusion of storage costs of raw materials where this question is asking about finished goods.
Think of it this way – finished goods sold immediately would have a lower cost than identical goods sold only after a period of time. Think of stock valuation problems – those goods fresh from the production line would have no storage costs attributable to them whereas other identical goods in inventory would have
Storage costs ARE included within inventory valuation of raw materials, but not for finished goods