What is the route-tag setting in an SD-WAN rule used for?

What is the route-tag setting in an SD-WAN rule used for?

A. To indicate the routes for health check probes. B. To indicate the destination of a rule based on learned BGP prefixes. C. To indicate the routes that can be used for routing SD-WAN traffic. D. To indicate the members that can be used to route SD-WAN traffic.