Which gateway is not an available option with AWS?

The correct answer is the Virtual Network Gateway, as it is specifically associated with Microsoft Azure and not AWS. In Azure, the Virtual Network Gateway is used to send network traffic between Azure virtual networks and on-premises locations through a VPN or Azure ExpressRoute.

In contrast, AWS provides several gateway options tailored for its cloud infrastructure. The Internet Gateway allows communication between instances and the internet, enabling public access to resources. The NAT Gateway is used to provide outbound internet access for instances in a private subnet, while the Transit Gateway acts as a hub that connects multiple VPCs and on-premises networks for more efficient routing. Therefore, the Virtual Network Gateway stands out because it does not belong within the AWS ecosystem, marking it as the correct answer.