It’s unlikely you’ll be asked this question directly, but it’s likely to be asked obliquely. (“Why Organization X?”) This is where you get to showcase the research you did on the organization and job description. You want to show that a) you know what the job description requires and b) that you’re a good fit. For example, “I’m really excited about the mix of work in this position. I enjoy client interaction, so I’d like to help out with the weekly legal information booth. But I’d also like to improve my courtroom skills, and expand on the work I did in the family law clinic in law school, so the opportunity to handle regular motion hearings is appealing.”