The correct answer is: B. ps
The ps command is used to display information about the processes currently running on a system. It can be used to list all processes, or to filter the list by process ID, user, command, or other criteria.
The au command is used to audit processes. It can be used to record information about when processes start and stop, what files they access, and what system calls they make.
The du command is used to display the disk usage of files and directories.
The pid command is used to print the process ID of the current process.
The None of the above option is incorrect because it does not list any of the commands that can be used to display the characteristics of a process.