For the following page reference string: 4, 3, 2, 1, 4, 3, 5, 4, 3, 2, 1, 5 — the number of page faults that occur using the Least Recently Used (LRU) page replacement algorithm with frame size 3 is:

1. A(A) 6
2. B(B) 8
3. C(C) 10
4. D(D) 12

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