Consider a reference string: 7, 0, 1, 2, 0, 3, 0, 4, 2, 3, 0, 3, 2, 1, 2, 0, 1, 7, 0, 1 of frame size FIFO algorithm. Determine the number of page faults.
1) 15
2) 12
3) 14
4) 16