Consider a paged memory system with a two-level page table. If the reference time to access the physical memory takes 20 nanoseconds (ns), how long does a paged memory reference take? Assume that the second-level page table is always in memory, and: There is no TLB, and the needed page is in main memory. There is a TLB, with access speed of 0.05 ns, the needed page is in main memory and The TLB does not contain information on this page. The TLB contains information on this page