The correct answer is A.
OBJ-1.11: The su command, which stands for substitute user, is used by a computer user to execute commands with the privileges of another user account. When executed, it invokes a shell without changing the current working directory or the user environment. When the command is used without specifying the new user id as a command-line argument, it defaults to using the system’s superuser account (user id 0). The command sudo is related and executes a command as another user but observes a set of constraints about which users can execute which other users can execute. The chown command is used to change the owner of the file, directory, or link in Linux. The ps command is used to list the currently running processes, and their PIDs and some other information depend on different options. It reads the process information from the virtual files in the /proc file system. The /proc directory contains virtual files and is known as a virtual file system. The passwd command changes passwords for user accounts. A normal user may only change the password for their account, while the superuser may change the password for any user.