I'm sorry to take so long to get back. All of the C atoms are sp2 hybridized. There are no sp3 hybridized C atoms
Here is a link to that post on Sunday.
http://www.jiskha.com/display.cgi?id=1295798102
According to your statement, all of the carbon (C) atoms in the given context are sp2 hybridized, and there are no sp3 hybridized carbon atoms. This indicates that the carbon atoms have formed three sigma bonds and have a trigonal planar geometry.
To verify this information, you can click on the link you provided. The link will redirect you to a webpage where the post from Sunday is displayed. By reading the post, you may find more details about the concept being discussed and gain a deeper understanding of why the carbon atoms are sp2 hybridized.