4. Suppose the daytime processing load of some computing server consists of 70% CPU activity and 30% disk activity. Customers are complaining that the system is slow. After doing some research, you have learned that you can upgrade your disks for $9,000 to make them 2.8 times as fast as they are currently. You have also learned that you can upgrade your CPU to make it 1.3 times as fast as it currently is for $6,000. a. [10 pts] Which would you choose to yield the best performance improvement for the least amount of money? Justify your answer through appropriate application of Amdahl's Law and a cost-benefit analysis similar to the one we did in lecture. b. [5 pts] Which option would you choose if you don't care about the money, but want a faster system? c. [5 pts] What is the break-even point for the upgrades? That is, what price would we need to charge for the CPU (or the disk - change only one) so the result was the same cost per 1% increase for both?