Consider a demand paging system with three frames, and the following page reference string: \[ 1\ 2\ 3\ 4\ 5\ 4\ 1\ 6\ 4\ 5\ 1\ 3\ 2. \] The contents of the frames are as follows initially and after each reference (from left to right):
The *-marked references cause page replacements. Which one or more of the following could be the page replacement policy/policies in use?