A Linux administrator needs to run a command in the background of a terminal, Which of the following commands will BEST accomplish this task?

The `bg` command is specifically used in shell job control to take a stopped process and move it to the background, allowing it to continue execution while freeing up the terminal. Although the `$$` part of the command is unusual in this context, the presence of `bg` is the only option that directly relates to running a command in the background after it has been initiated.

`./run_application +$` is not a valid or standard command for running an application in the background; the `+` and `$` symbols do not serve this purpose. C: `./run_application` runs the application in the foreground, blocking the terminal until it completes or is manually suspended. D: `./run_application $` runs the application in the foreground, passing the value of the last argument as an additional argument, and does not background the process.