When I upload an internal-testing in Google play store, I have three options (in the top right hand side).

However, "phones, tablets, chrome os" and "instant apps only" options are confusing for me.
In both the options, I can upload a .aab file which can contain both the normal app and the instantapp.
I see the same in the closed testing and production, but not in the open testing. It does not have the instant apps only option. One possible reason is I do not have any open-testing-track set up.
Therefore:
- Can someone explain me the difference between "phones, tablets, chrome os" and "instant apps only" options.
- I want to test an app with both app and an instantapp (a qr code opens the instantapp, later the user can opt to install the main app). So what to upload?