a. LRU is considered a good page-replacement policy. Describe what a good page replacement policy should do, what LRU(least-recently-used) replacement is. b. Consider the following page reference string: 7, 2, 3, 1, 2, 5, 3, 4, 6, 7, 7, 1, 0, 5, 4, 6. Assuming a TLB with 3 frames, how many TLB miss would occur for the LRU replacement algorithms. c. Fill in the blanks below with the page references. (if necessary, you can make more frames for your answer.) 7