A company is running its AWS infrastructure across two AWS Regions. The company has four VPCs in the eu-west-1 Region and has two VPCs in the us-east-1 Region. The company also has an on-premises data center in Europe that has two AWS Direct Connect connections in eu-west-1.
The company needs a solution in which Amazon EC2 instances in each VPC can connect to each other by using private IP addresses. Servers in the on-premises data center also must be able to connect to those VPCs by using private IP addresses.
What is the MOST cost-effective solution that meets these requirements?

A. Create an AWS Transit Gateway in each Region, and attach each VPC to the transit gateway in that Region. Create cross-Region peering between the transit gateways. Create two transit VIFs, and attach them to a single Direct Connect gateway. Associate each transit gateway with the Direct Connect gateway.
B. Create VPC peering between each VPC in the same Region. Create cross-Region peering between each VPC in different Regions. Create two private VIFs, and attach them to a single Direct Connect gateway. Associate each VPC with the Direct Connect gateway.
C. Create VPC peering between each VPC in the same Region. Create cross-Region peering between each VPC in different Regions. Create two public VIFs that are configured to route AWS IP addresses globally to on-premises servers.
D. Create an AWS Transit Gateway in each Region, and attach each VPC to the transit gateway in that Region. Create cross-Region peering between the transit gateways. Create two private VIFs, and attach them to a single Direct Connect gateway. Associate each VPC with the Direct Connect gateway.