You are reevaluating the pump choice that was made last year by your boss. the expected cost savings have not occurred because the pump is too small. choice a, at $90,000, is to replace the pump with one that is the right size and sell the old one. choice b , at $100,000, is to buy a small pump to use in tan- dem with the existing pump. the two-pump solution has slightly higher maintenance costs, but it is more flexible and reliable. what criteria should you use? which choice would you recommend, and why?