Which page replacement policy sometimes leads to more page faults when size of memory is increased?

Let the page reference and the working set window be c c d b c e c e a d and 4, respectively. The initial working set at time $$t = 0$$ contains the pages {a, d, e}, where a was referenced at time $$t = 0, d$$ was referenced at time $$t = -1,$$ and $$e$$ was referenced at time $$t = -2.$$ Determine the total number of page faults and the average number of page frames used by computing the working set at each reference.

A computer system has 6 tape drives, with n process completing for them. Each process may need 3 tape drives. The maximum value of n for which the system is guaranteed to be deadlock free is:

Which of the following regular expression identities are true?