The goal of your answer is to show the interviewer that you understand the logistical elements involved in a large group photo. You want them to gain a sense of your competency and comfort level with this kind of photo.

The best approach to answering this question is to share an example and explain how you approached it as a photographer. If you don't have a good example, focus on the logistical challenges of a large group photo.

Large group photos can be logistically complex to capture. It involves a lot of planning. You need to understand what kind of background your client wants and the environmental factors, and you need to communicate with several people at once. I recently captured a large group photo of workers on an assembly line. I scouted the location to find a place that would have adequate power for lighting and be safe for everyone, given it was an assembly line, and made sure I had a way for everyone to hear my instructions. To capture the photo, I needed to stand 30 yards away from the group. When I scouted, I realized how loud it was on the assembly floor, so I arranged for a couple of assistants to stand close to the group. The assistants and I were able to coordinate instructions using a walkie-talkie.