Don't get caught up in this trick question. The answer to this question is that you work best in EITHER a solo or team environment. Give an example of a successful time you've worked in each situation to give the interviewer that piece of mind. Are you the one that brings people together and encourages healthy working relationship? Do you enjoy working on your own because you are the most productive when uninterrupted?
"I can work on my own or within a team. I always learn something new and meet goals in either setting that I am in."