A typical interview question to determine what you are looking for your in next job, and whether you would be a good fit for the position being hired for, is "What challenges are you looking for in a position?" The best way to answer questions about the challenges you are seeking is to discuss how you would like to be able to effectively utilize your skills and experience if you were hired for the job. You can also mention that you are motivated by challenges, have the ability to effectively meet challenges, and have the flexibility and skills necessary to handle a challenging job. You can continue by describing specific examples of challenges you have met and goals you have achieved in the past.