c) Consider the page-reference string from t = 1 until t = 20, as shown in Fig. 1(c). Assume that there are four frames available and that they are all initially empty. 1 a 4 5 6 b 2 3 b d 7 8 9 10 11 12 13 14 15 16 17 18 19 20 e f b g b b g a h f a d e Fig. 1(c). Sample of Page Address Stream g i. Show the frame allocation for each of the following page replacement policies: First-in- first-out, optimal, and least recently used. (6 marks) ii. Discuss and analyze the best policy by finding each policy's relative performance concerning page faults. (2 marks) (2 marks) iii. Design a strategy to reduce the number of page faults. iv. At t = 12 to t = 20, Frame 4's protection bit is set to 1, i.e., cannot be replaced. Show the page replacement using first-in-first-out. (2 marks)