A company's IT associate has been asked to switch to single-user mode on a running Linux server in order to perform some troubleshooting. Of the options below, which is the best way of doing this?

`su single` attempts to switch to a user named 'single', which is not a standard way to enter single-user mode.

`init singleuser` is not a valid `init` command argument for entering single-user mode; the standard argument is '1' or 's'.

`lsu 1` is not a recognized Linux command for changing runlevels or entering single-user mode.

The `init 1` command instructs the `init` process to change the system's runlevel to 1, which corresponds to single-user mode. In this mode, most services are stopped, and only the root user is logged in, providing a minimal environment suitable for system maintenance and troubleshooting without interference from other processes or users.