I did not knowingly install an ad blocker on Firefox, but clearly I have one, because several sites I visit ask me to disable it. When I try to do so, I'm presented with a long list of ad blockers, and am asked to choose mine and disable it. How do I find out what my ad blocker is? I've tried to find this on Firefox, with no success. I hope someone can walk me through this.

Thanks, Janet Shapiro