Which configuration allows network devices to support both IPv4 and IPv6 routing simultaneously?

The correct choice refers to a configuration known as Dual Stack, which enables a network device to simultaneously support both IPv4 and IPv6 protocols. This is particularly useful in transitional phases where both addressing schemes are operational, allowing devices to communicate using either protocol depending on the situations and requirements of the network.

With Dual Stack, a device is equipped with two separate stacks for each protocol, which means that it can operate efficiently in environments where IPv4 is still prevalent while also embracing the advancements of IPv6. This facilitates a gradual migration to IPv6 without disrupting existing IPv4 services, providing full compatibility for both protocols.

Other options detail specific mechanisms or attacks that do not implement dual communication of both IPv4 and IPv6. For example, 6to4 is a method for encapsulating IPv6 packets over an IPv4 network, primarily serving to aid in IPv6 migration but not allowing a device to support both protocols natively at the same time like Dual Stack does. Dynamic ARP Inspection is a security feature that prevents ARP spoofing attacks; it does not relate to supporting both IPv4 and IPv6. ARP Spoofing itself is an attack technique, unrelated to the routing capabilities of devices concerning IPv4 and IPv6.