please answer these for me

1. Why has the average US company's current ratio decreased since 1981? A. Better accounts payable management B. Better inventory management C. Better accounts receivable management D. Both B and C E. None of the above 2. Which of the following are true? A. Operating cycle equals average age of inventory plus average payment period B. Cash conversion cycle equals operating cycle plus average collection period C. Cash conversion cycle equals operating cycle minus average payment period D. Average age of inventory equals operating cycle plus average collection period E. None of the above. 3. During 2021, Bismuth Cartridge Corporation had an average daily cost of goods sold of $13 million, average accounts receivable of $91 million, average inventory of $104 million. What was Bismuth's average age of inventory for the year? A. 8 days B. 7 days C. 1 day D. 91 days E. None of the above 4. If a firm wishes to shorten its operating cycle, it should A. Turn over inventory as slowly as possible B. Offer generous credit terms to customers with long repayment periods C. Invert its cash collection cycle D. Turn over inventory as quickly as possible E. None of the above