Final answer:
The MFU page replacement algorithm operates on the premise that pages used most frequently in the past will not be needed soon, a concept contrary to the given options. Therefore, none of the given reasons accurately explain the rationale for using MFU in page replacement.
Step-by-step explanation:
The MFU (Most Frequently Used) page replacement algorithm is based on the argument that pages that have been used most frequently in the past will likely not be used again shortly. Thus, the reason for using the MFU page replacement algorithm is:
a) an actively used page should have a large reference count
This statement aligns with the LFU (Least Frequently Used) algorithm, not the MFU. The idea behind LFU is that pages that have been used less frequently are less likely to be used in the immediate future.
b) a less used page has more chances to be used again
This statement also aligns more closely with LFU than MFU.
c) it is extremely efficient and optimal
This is not strictly true; the MFU algorithm is not guaranteed to be efficient or optimal in all situations. The most optimal page replacement algorithm in theory is the OPT or Optimal Page Replacement algorithm, which can be impractical to implement.
d) All of the mentioned
Based on the above explanations, none of the mentioned reasons fully justify the use of the MFU page replacement algorithm. Hence, none of the options accurately describe the rationale behind using MFU.