How do you switch to another user in the terminal?

The command to switch to another user in the terminal is represented accurately by the command "su username." This command invokes the 'su' (substitute user) function, which allows a user to authenticate and change to another user's account within the command line interface. When executed, the user is prompted for the password of the specified username being switched to. If the right credentials are provided, the terminal session will be transformed to the specified user's environment, updating shell variables, permissions, and paths relevant to that user.

The other choices provided do not correspond to valid commands in standard Linux systems for switching users. "switch username," "user username," and "change username" do not exist as recognizable commands in the terminal and would return an error if entered, underscoring the importance of knowing the correct syntax for user management in Linux.