Q1. Page fault occurs when:
A the page is present in memory
B a deadlock occurs
C the page is not present in memory Correct
D buffering occurs
Explanation
A page fault is raised when the processor tries to access a page that is not currently loaded in main memory. The operating system then locates that page on secondary storage and brings it into memory. If the page is already present in memory, the access continues normally and no page fault is needed. A deadlock is a process-synchronisation problem, not a virtual-memory missing-page event. Buffering is temporary data holding during input/output, so it is unrelated to the page-table miss described here.