A. Create an AWS Transit Gateway. Attach the shared VPC and the authorized business unit VPCs to the transit gateway. Create a single transit gateway route table and associate it with all of the attached VPCs. Allow automatic propagation of routes from the attachments into the route table. Configure VPC routing tables to send traffic to the transit gateway.
B. Create a VPC endpoint service using the centralized application NLB and enable the option to require endpoint acceptance. Create a VPC endpoint in each of the business unit VPCs using the service name of the endpoint service. Accept authorized endpoint requests from the endpoint service console. Most Voted
C. Create a VPC peering connection from each business unit VPC to the shared VPC. Accept the VPC peering connections from the shared VPC console. Configure VPC routing tables to send traffic to the VPC peering connection.
D. Configure a virtual private gateway for the shared VPC and create customer gateways for each of the authorized business unit VPCs. Establish a Site-to-Site VPN connection from the business unit VPCs to the shared VPC. Configure VPC routing tables to send traffic to the VPN connection.