Correct Option: A

In Belady’s anomaly, if number of frames are increased then number of page faults increases. This behaviour found only with FIFO.
The First In, First Out (FIFO) page replacement algorithm is a low-overhead algorithm. In FIFO, the operating system keeps track of all the pages in memory in a queue. The queue is managed in a way that the most recent arrival is placed at the back, and the earliest arrival in front. T the time of page replacement, oldest page is selected to get replaced. Practical implementation of FIFO is not very good as the algorithm experiences Belady’s anomaly.
In FIFO when the number of frames increases then, the number of page faults also increases and this behaviour is found by Belady’s anomaly. Thus, FIFO have this Belady’s anomaly, e.g., in FIFO for three frames the reference string 1, 2, 3, 4, 1, 2, 5, 1, 2, 3, 4, 5
There are 9 page faults and for four frames for the reference string there will be 10 faults.