Answer:
The correct answer would be option B, They already know of open positions that you would be good for.
Step-by-step explanation:
The concept of Employment agencies are gaining fame now a days. These are the companies which know about most of the job openings in smaller to bigger companies in the industries. They take your credentials, put them in their systems, match it with the records and finds the best suitable job for you which would be most appropriate for you according to your credentials and preferences. So the benefit of having an employment agency find you a job is that they already know of open positions that you would be good for, otherwise if you find the jobs yourself, it will be time consuming as well as it might not be suitable for you.