Final answer:
Page buffering in Linux helps reduce page fault overhead by using a buffer to store frequently accessed pages, thus reducing the need for disk I/O, which is the correct answer to how it reduces overhead.
Step-by-step explanation:
Page buffering in modern operating systems like Linux is a technique used to reduce the overhead associated with page faults. A page fault occurs when a program tries to access data that is not in the main memory, causing the system to fetch it from the disk. Page buffering employs the use of a page buffer, which holds frequently accessed or recently used pages. This reduces the need for disk I/O because data can often be found in the buffer rather than on the slower disk. As such, the correct answer to the question is A. Reduces the need for disk I/O.
This strategy does not eliminate the need for virtual memory (B), as virtual memory is used to give the impression of a large contiguous block of memory, nor does it directly reduce CPU utilization (C) or enhance network bandwidth (D). The main purpose of page buffering is to lessen the frequency and impact of page faults by making the required data available in the faster-access memory buffers.