I think it belongs on 8949/Schedule D.

On the Schedule C, look at line A (principal business).  Above that are a bunch of "Quickzoom" buttons.  Look at the top Quickzoom button.

If you want it on 4797, I think I would just categorize it as an Amortized Intangible.

You can make direct entries on the 4797

Was it all paid at once or during one calendar year, or was it an installment sale for Form 6252?