A company that has SAP workloads on premises plans to migrate an SAP environment to AWS. The company is new to AWS and has no prior setup. The company has the following requirements: - The application

A Network Load Balancer distributes incoming traffic to multiple targets and does not provide the site-to-site connectivity needed for on-premises users to reach SAP systems in AWS.

AWS Site-to-Site VPN establishes an encrypted tunnel between the on-premises network and the AWS VPC, allowing on-premises end users to securely access SAP systems hosted in AWS over the internet without publicly exposing the SAP portals.

Separating application and database servers into different VPCs requires VPC peering or Transit Gateway for inter-server communication, which adds both cost and complexity - directly conflicting with the requirement to minimize communication costs.

Placing the application server and database server in different subnets within the same VPC, separated by network ACLs, provides the required network isolation while keeping inter-server traffic within the same VPC - which is free and lower latency than cross-VPC communication.

AWS Direct Connect provides a dedicated private connection but is significantly more expensive than Site-to-Site VPN and is unnecessary for the described requirements, making it a cost-inefficient choice for a company new to AWS.