A network engineer is implementing BFD configuration changes on a customer's equipment. How is the bfd interval configuration on the interface disconnected?

A change in the interface's operational status (e.g., going down) causes the BFD session to terminate, but it does not remove or 'disconnect' the underlying BFD interval configuration from the running configuration.

Changing the IPv4 or IPv6 address on an interface might cause the existing BFD session to break and re-establish, but the `bfd interval` configuration itself remains applied to the interface.

Removing a BFD-configured subinterface disconnects BFD for that specific subinterface, but the question asks about the 'main interface' and D is a more encompassing answer if the main interface itself is removed.

If the main interface, whether a physical port or a logical main interface, is removed from the device's configuration (e.g., via a 'no interface' command), all associated configurations, including any BFD interval settings on that interface and its subinterfaces, are also implicitly removed or become non-functional, thus 'disconnecting' the BFD configuration.