FAT stands for

In Disk Operating System (DOS), FAT stands for Option C: File Allocation Table. The File Allocation Table is a crucial part of the file system used by DOS and other operating systems to manage and allocate space on storage devices such as hard drives and floppy disks.

Option A, "File Accommodation Table," and Option B, "File Access Tape," are not correct terms related to FAT in DOS.
Option D, "File Activity Table," is also not a correct term related to FAT.

Therefore, the correct answer is Option C: File Allocation Table.