"Source" Picklist seems irrelevant to applicant

"Source" Picklist seems irrelevant to applicant

I'd like to speak with someone over the phone about how to solve my issue. I'm working on building the candidate application for the public careers site but cannot understand why the "Source" picklist is there. It is completely unnecessary for the applicant and I'm frustrated because I cannot remove it nor can I change the options in the picklist. Please help me. Thank you.