After running the command umount /mnt, the following error message is displayed:
umount: /mnt: device is busy.
What is a common reason for this message?
A.
The kernel has not finished flushing disk writes to the mounted device.
B.
A user has a file open in the /mnt directory.
C.
Another file system still contains a symlink to a file inside /mnt.
D.
The files in /mnt have been scanned and added to the locate database.
E.
The kernel thinks that a process is about to open a file in /mnt for reading.