The interviewer is trying to gauge your level of commitment to your current profession and interest in other fields. This question is also an opportunity to showcase any transferable skills you may have that could be applied to other professions if necessary. It's important to answer honestly and show that you have thought about other options, but ultimately you are dedicated to your current career path. However, if you decide to share another profession you are interested in, the best answer is to choose a profession that is closely related to the position you are interviewing for, or at least in the same field. Choosing a similar job that might be above your experience level shows you are committed to your profession and professional growth.