(i) True, If a user-level process was allowed to modify its own page table entries, then it could access physical memory being used by other processes or the OS kernel. Kernel mode is required to modify page table entries.
(ii) In general, it is False as scheduler only schedules processes based on a process's attributes. But it may be True for some schedulers such as priority based scheduler.
(iii) False, We know that SRTF is the best known algorithm but it cannot be implemented in OS as we do not have insight of future references.
Reference: https://cs162.eecs.berkeley.edu/static/exams/fa13-mt1-solutions.pdf
