Which solution meets these requirements?

Explanations:

Provisioning a Direct Connect gateway allows for redundancy and connectivity to multiple regions. By deleting the existing private virtual interface and creating a new private virtual interface on each Direct Connect connection, both can connect to the Direct Connect gateway, which then connects to the single VPC. This setup allows future scalability across regions.

This option retains the existing private virtual interface and simply adds a second connection with a new private virtual interface. However, this setup does not provide redundancy through a Direct Connect gateway and limits future expansion to other regions, as the two connections would not share connectivity.

While this option keeps the existing private virtual interface and adds a new connection, it incorrectly proposes a public virtual interface on the new connection. This setup does not satisfy the requirement for private connectivity to the VPC and does not enable multi-region connectivity.

Although using a transit gateway might seem advantageous, this option incorrectly suggests deleting the existing private virtual interface. It would require creating a new private virtual interface for each connection and connecting them to the transit gateway, which is unnecessary since a Direct Connect gateway is a better fit for enabling redundancy and multi-region connectivity.