d) [Chapter 17] For small animal surgery services, a computerized heart-lung machine must have a reliability of 0.995. Two technologies are available for the heart-lung machine: one produces a 0.999 reliability for $50,000. Another produces a component with 0.90 reliability for $20,000. What is the most economical policy to attain the target degree of reliability: one high-reliability system or a parallel set of low-reliability systems? Why?