Page Replacement Policies

Step 1: Understanding Page Replacement Policies.
A page replacement policy is used to decide which page to remove from memory when new pages need to be loaded.

- **Statement (A):** "The goal of a page replacement policy is to try to remove the page most likely to be referenced in the immediate future." This is not entirely true for all page replacement algorithms, as algorithms like FIFO and LRU are based on different principles. Therefore, this is not always a valid statement.

- **Statement (B):** "First in First Out (FIFO) and Least Recently Used (LRU) are the two most common page replacement algorithms." This statement is true. FIFO and LRU are indeed the two most widely used algorithms in page replacement.

- **Statement (C):** "The FIFO algorithm selects for replacement the page that has been in memory the longest time." This is correct. FIFO simply removes the page that has been in memory the longest, regardless of how recently it was used.

- **Statement (D):** "LRU algorithm is based on the assumption that the least recently loaded page is a better candidate for removal than the least recently used page." This is incorrect as written, as LRU is based on the assumption that the least recently **used** page is a better candidate for removal, not the least recently **loaded** one.

Step 2: Conclusion.
Thus, the correct answer is (4) B, C, and D only, as these statements accurately describe the page replacement policies.