Better to say more or less?

In an interview with a top 10 law firm, how many law firms and what size of law firms should you admit to have applied to?

In an interview with a top 10 law firm I was asked what firms I had also applied to? I just reeled off my list of firms, which were quite diverse to say the least, including a number of smaller firms and even a high street one from my hometown. The interviewer looked a little confused as to my choices and challenged me as to why I had made this decision, which I didn’t answer very well. What should I have done in this situation – should I only have mentioned top 10 law firms? If I did this should I only admit to applying to two or three or say all ten?