PLEASE answer the question

(Choose only one answer) In FIFO (first in first out) page replacement algorithm, when a page must be replaced, then Select one: O a. the least recently used page is selected O b. the newest page is selected O c. none of the mentioned O d. the oldest page is selected (Choose only one answer) When several processes access the same data concurrently and the outcome of the execution depends on the particular order in which the access takes place is called Select one: a. race condition O b. critical condition O c. essential condition O d. dynamic condition for (Choose only one answer) In UNIX, the return value for the fork system call is the child process and for the parent process. Select one: O a. A nonzero integer, Zero O b. A Negative integer, Zero O c. Zero, A Negative integer O d. Zero, A nonzero integer