4. The sequence below shows the page number used from left to right. How many times of page fault will occur if the LeastRecently Used (LRU) page replacement policy is used and the frame size is 5?  1 3 6 7 2 4 6 2 5 6 9 1 2 1 4 3 4 5 7 8
(A) 5 times
(B) 6 times
(C) 7 times
(D) 8 times
(E) 9 times