An administrator discovers a pending job for the at command. Which of the following does the administrator need to use to remove it?

The `atrm` command (at remove) is specifically designed to delete jobs that have been scheduled using the `at` command by referencing their job number. This provides direct control over the `at` job queue, allowing for the cancellation of future tasks.

`atq` lists pending `at` jobs, but the `-r` option is not standard for removal; `atq` is for querying, not removing jobs from the queue.

`at -e` is used to edit an `at` job's details, not to remove the job itself from the queue.

`rmat` is not a standard Linux command for managing `at` jobs.