Answer: D. 120
Explanation:
The first machine being assigned a job can be assigned one from 5 jobs.
Once that happens, the next machine can only be assigned from any one of 4 jobs.
The next machine, any one of 3 jobs.
The next machine, any one of 2 jobs.
The Last machine gets the last job remaining.
The different ways a job can be assigned therefore are;
= 5 * 4 * 3 * 2 * 1
= 120