Answer : A page has been modified after being loaded into cache Because
When a bit is modified by the CPU and not written back to the storage, it is called as a dirty bit. This bit is present in the memory cache or the virtual storage space.A dirty bit is a flag that indicates whether an attribute needs to be updated. Such situations usually occur when a bit in a memory cache or virtual memory page that has been changed by a processor but has not been updated in the storage.