The correct answer is: A. /usr
The /usr directory is a system directory that contains subdirectories for local programs and executables for user and administrative commands. It also contains subdirectories for system libraries, man pages, and other system files.
The /tmp directory is a temporary directory that is used to store files that are not needed after the current session.
The /opt directory is a directory for optional software that is not part of the base system.
The /mnt directory is a mount point for temporary filesystems.
E. None of the above is not a correct answer.