A student has claimed that ''in the abstract, the basic page replacement algorithms (FIFO, LRU, optimal) are

Question:

A student has claimed that ''in the abstract, the basic page replacement algorithms (FIFO, LRU, optimal) are identical except for the attribute used for selecting the page to be replaced.''
(a) What is that attribute for the FIFO algorithm? LRU algorithm? Optimal algorithm?
(b) Give the generic algorithm for these page replacement algorithms.