plz try to solve this question with steps

3. Task 3: Consider a page-reference string having minimum 20 page references with only five unique page references. How many page faults would occur for the following replacement algorithms, assuming three frames a) Least Recently Used replacement b) First In First Out replacement c) Optimal Page Replacement? Remember that all frames are initially empty, so your first unique pages will all cost one fault each. Evaluate the performance of each one of the algorithms and write the pseudocode for the replacement algorithm that gives the minimum page faults. (12+8=20 marks)