A computer has twenty physical page frames which contain

A computer has twenty physical page frames which contain pages numbered 101 through 120. Now a program accesses the pages numbered 1, 2,..., 100 in that order, and repeats the access sequence THRICE. Which one of the following page replacement policies experiences the same number of page faults as the optimal page replacement policy for this program?

1. Least-recently-used
2. First-in-first-out
3. Last-in-first-out
4. Most-recently-used

Pages 1, 2, 3,... 19, 20, 21,... 100, 1,... 19, 20, 21,... 100