3. Consider the following reference string: How many page faults would this string produce under the FIFO page replacement strategy with three frames? 4 2 21 4 35 24 5214 31 a. b. _How many page faults would this string produce under the OPT replacement strategy with three frames? 4 2 21 4 35 2 4 5 21 4 31 How many page faults would this string produce under the LRU replacement strategy with three frames? 4 2214 35 2 4 5 214 3 1 c