"Common" parent page is not in the list for creating a custom page

I am creating a custom category page and following directions from this article (http://lithosphere.lithium.com/t5/Customer-Connection-Knowledge/Creating-a-custom-Category-page-using-Studio/ta-p/6121) but I don't see an option for a "common" page.  I have used the QandA Category as a parent page, but this requires me to change all the content in the layout with the exception of two components (header and footer).  I'd like to rearrange less components so I can speed up this process...any thoughts on which parent page to use?

Thanks,

Angela