I think 'they need work' should be accepted as well.
"They need the job" would probably be used much less often than "they need a job".
"A job" would be non-specific; any job will do. "The job" would be a specific job.
in Portuguese "they need a job" would be "eles precisam de um emprego",,different from what Duo proposed. For me, in English it works the same way.