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 thinks that a process is about to open a file in /mnt for reading.

B.
The files in /mnt have been scanned and added to the locate database.

C.
The kernel has not finished flushing disk writes to the mounted device.

D.
A user has a file open in the /mnt directory.

E.
Another file system still contains a symlink to a file inside /mnt.

Explanation: