Trying to make a C major over A chord?

Hi, for reasons, I am trying to make a C major over A chord per a suggestion from my comp. teacher. How can I create that chord? I can’t figure out a way to do it with Hooktheory’s tools.

Thank you.

I’m assuming that you’re referring to C/A.

I’m trying to replicate this, and the closest I’ve gotten is C6/G (C major, add 13, 2nd inversion). Of note, the 3rd “inversion” is grayed out.

With a single chord, not possible, but if you have Hookpad+, you can sacrifice a melody voice to place an A in the bass.

If you’re talking “a C major chord on top of an A major chord” then you’ll need an A major chord in the chord section, and 3 melody voices for the C chord.

Thanks for the reply. I also noticed the third inversion was greyed out when exploring. Oh well.