18) The days held in inventory ratio measures: A) the percentage change in inventory over the past year. B) the average length of time it takes a company to sell its inventory. sales required to keep a company's average inventory on the books. D) the average length of time it takes the company's suppliers to deliver its inventory. 19) If the risk-free rate of interest (1) is 4%, then you should be indifferent between receiving $1000 in one-year or how much today