A two-level page table is created to enable paging for a 4GB logical address space. In this scheme, the page size is 4 KB, and each page table entry has a size of 4 bytes. The root page table can fit in a single 4 KB page. a. How much memory space is needed in total for this two-level page table? b. Assume you want to implement a hashed page table for the same addressing scheme, using a hash function that maps the 20-bit page number into a 12-bit hash value. The table entry has a size of 8 bytes, containing the page number, the frame number, and a chain pointer. How much memory space does the hashed page table take? Compared to the two-level page table, how much memory space has been saved with the hashed page table? c. Suppose that the page size and the size of page table entries stay the same, how many levels of page tables would be required to map a 64-bit address space, if the top-level page table still needs to fit into a single page