A job I am applying for asked me how I financed my higher education. Is this a red flag for discrimination?

The job is located in a very wealthy area and I'm afraid they're going to discriminate against me for using scholarships and student loans to pay for college. Are there any legitimate reasons for an interviewer to ask how I payed for school, or is this a way for them to weed out "undesirable" candidates? The question seems very inappropriate to me.