单选题：Assume that a system with memory mapping done on a page basis an

Assume that a system with memory mapping done on a page basis and using a single-level page table, the necessary page table is always in memory. The system has TLB. The memory reference takes 100ns, and the TLB access takes 20ns. If the TLB hit rate is 80%, what is the effective memory access time? @[B](1)
A. 100ns
B. 140ns
C. 200ns
D. 220ns




A.100ns
B.140ns
C.200ns
D.220ns


答案：B