A network engineer must update a hybrid network to support IPv6 for a VPC-hosted application. The existing infrastructure (transit gateway, Direct Connect, Site-to-Site VPN) cannot be modified. The VPC is dual-stack and instances must be prevented from being directly reachable on their IPv6 addresses from the internet, while still allowing outbound internet access. What is the most operationally efficient solution?

The correct option is the most operationally efficient because it leverages existing infrastructure where possible and introduces new components only when necessary. Updating the Direct Connect transit VIF is the correct approach for enabling IPv6 over an existing Direct Connect connection. Creating a new VPN connection is required because existing Site-to-Site VPN connections cannot be modified to support IPv6; a new one must be created. An Egress-Only Internet Gateway (EIGW) is essential for IPv6 instances to initiate outbound connections to the internet while preventing unsolicited inbound connections, fulfilling the requirement for no direct internet reachability. Finally, updating security groups and route tables ensures proper traffic flow. The other options are incorrect because: The second option incorrectly suggests updating an existing VPN connection for IPv6, which is not possible. The third option incorrectly suggests creating a new Direct Connect transit VIF, when the existing one can be updated. The fourth option incorrectly suggests adding a NAT Gateway, which is for IPv4; an Egress-Only Internet Gateway is needed for IPv6 outbound internet access.