What should the solutions architect recommend?

Explanations:

This option creates a separate AWS Direct Connect and VPN connection for each VPC. While it would provide direct access to the on-premises data center, it could lead to increased complexity and management overhead as well as higher costs due to multiple connections. It does not leverage a centralized approach that can scale more efficiently.

This approach suggests creating VPC peering between all VPCs and the Production VPC. However, VPC peering does not allow transitive routing, meaning that the Testing and Development VPCs would not be able to access the data center through the Production VPC. This creates limitations in scalability and connectivity.

This option proposes connecting VPNs from all VPCs to a central VPN in the Production VPC, which then connects to the data center. Similar to option B, it relies on transitive routing through the Production VPC, which may not work effectively as VPN connections have bandwidth limitations and could lead to a bottleneck. It also complicates the architecture and introduces single points of failure.

This option utilizes an AWS Transit Gateway in a dedicated Network VPC, which simplifies and centralizes connectivity. By establishing a single AWS Direct Connect connection to the data center and attaching all other VPCs to the Transit Gateway, this solution enhances scalability, provides secure and efficient routing, and minimizes complexity in management. This architecture aligns with AWS best practices for connecting multiple VPCs to on-premises resources.