Need help in Operating Systems. please answer the folllowing questions.

Assume a physical memory of 4 page frames and initially all frames are empty. Given the reference string 4, 2, 5, 0, 1, 2, 1, 4, 5, 1, 0, 1, 5, 2,4, show the page replacement procedures and give the number of page faults for the following page replacement policies: 1. OPT 2. LRU 3. Second Chance We use Simulator paging-multilevel-translate.py to study how the address translation work with the multi-level paging table. We ran a configuration and obtain a complete dump of each frame of physical memory as shown in this file . A few column index lines are inserted for easy reading. "page" on the first column means the physical frame. The value of PDBR is 30 (decimal), i.e., the page directory is held in Page 30. For the following virtual addresses, please fill in the blanks for PA with the corresponding physical address. If invalid, put Invalid in the black. In order to obtain the PA, you need to obtain the index and the correspondingly content of PDE, PTE, and Offset, respectively. We use Simulator paging-multilevel-translate.py to study how the address translation work with the multi-level paging table. We ran a configuration and obtain a complete dump of each frame of physical memory as shown in this file . A few column index lines are inserted for easy reading. "page" on the first column means the physical frame. The value of PDBR is 30 (decimal), i.e., the page directory is held in Page 30 . For the following virtual addresses, please fill in the blanks for PA with the corresponding physical address. If invalid, put Invalid in the black. In order to obtain the PA, you need to obtain the index and the correspondingly content of PDE, PTE, and Offset, respectively