A candidate asked me this question and I felt it a good way to understand what is being expected of the candidate in the interview.
It is basically straightforward question which can throw more light on the interviewing process.
“If any candidates have already been interviewed – what reasons were given for their not being shortlisted. ”
If you can get the recruiter to share with you the details as to why his/her earlier candidates were not shortlisted – you can accordingly modify your presentation.