Final answer:
The AWS Transit Gateway is the best solution for connecting VPCs and on-premises networks due to its simplicity, scalability, and minimal operational overhead.
Step-by-step explanation:
The simplest solution for connecting VPCs and on-premises networks through a central hub with the least operational overhead is the AWS Transit Gateway.
A Transit Gateway acts as a network transit hub, allowing you to connect your VPCs, data centers, and remote offices in a hub-and-spoke model, simplifying network architecture and management.
Compared to individual VPN connections, AWS Direct Connect, or VPC peering connections, the AWS Transit Gateway is more scalable and easier to manage, providing a single gateway for all connections without the need to establish a complex peering relationship between each network.