The correct answer is D. prompt> # help.
GNU screen is a terminal multiplexer that allows you to create multiple virtual terminals within a single physical terminal. This can be useful for running multiple programs at the same time, or for keeping your work organized.
To use GNU screen, you first need to start a screen session. You can do this by typing the following command:
screen
This will create a new screen session and open a new window. You can then type commands in this window as you would normally.
To create a new window in a screen session, you can type the following command:
Ctrl+a c
This will create a new window and switch to it. You can then type commands in this window as you would normally.
To switch between windows in a screen session, you can use the following commands:
Ctrl+a b
Switch to the previous window.
Ctrl+a n
Switch to the next window.
To detach from a screen session, you can type the following command:
Ctrl+a d
This will detach you from the screen session, but it will keep the session running in the background. You can then reconnect to the session by typing the following command:
screen -r
To exit a screen session, you can type the following command:
Ctrl+a \
This will exit the screen session and close all of the windows.
The command prompt> # help will display a list of all of the available commands for GNU screen. You can then use these commands to control your screen session.
The other options are not correct because they do not start a screen session or use any of the commands available in GNU screen.