Is a circle a polygon? If it is a polygon then what is the name of that polygon?

I have this question from our geometry teacher. It is hard. My friend said it is a paerigon derived from perihelion. My answer is apeirogon because a circle have infinite sides. I found here that it is a monogon because it is one sided. I need an answer in 6 hours or I'll get 0 on that ignment. Please I'm begging someone expert to answer this question. I've been tring to find for answers but they are all different.