What is the easiest way to enable SD-Access for all your remote sites after you...

Use a separate fabric domain for each site and use the traditional physical network as the underlay.

Threat all the sites as one fabric domain and use the traditional physical network as the underlay.

Threat all the sites as one fabric domain and use SD-WAN as the underlay.

Use a separate fabric domain for each site and use SD-WAN a s the underlay.