Final answer:
The valid-invalid bit in computer memory management indicates whether a page is in memory or not. If set to valid, it means the page is stored in physical memory; if invalid, the page is not present in memory and may need to be fetched from secondary storage.
Step-by-step explanation:
In the context of computer memory management, the valid-invalid bit is a flag related to the use of virtual memory systems, particularly in a paging scheme. Each page is associated with a valid-invalid bit in the page table to quickly determine the state of the page.
When the valid-invalid bit is set to 'valid', it indicates option (c) the page is in memory, meaning that the page is currently stored in physical memory (RAM), and any references to that page can be directly resolved to a physical address. Conversely, if the bit is set as 'invalid', it commonly means that the page is not currently in physical memory, which could be due to it being stored on a slower, secondary storage device (like a hard drive) or because it has not been allocated at all. This facilitates page fault handling when the system needs to determine whether to fetch a page from secondary storage or take other measures.