Correct Option: B

A page table is the data structure used to store the mapping between virtual addresses and physical addresses. A page table is used by a virtual memory system in a computer operating system. Virtual addresses are the addresses which are unique to the accessing process while physical addresses are the addresses that are unique to the CPU, i.e., RAM. Page frame number is essential content in each of the page table. Virtual page number may not be store entirely in the page table and thus, cannot be considered as the essential content.