A company collects data from a vendor. The vendor stores its data in an Amazon RDS for MySQL database in the vendor's AWS account. The company’s VPC has no internet gateway, Direct Connect, or Site-to-Site VPN. The company needs access to the vendor database. Which solution meets this requirement?

The correct solution uses AWS PrivateLink, which allows private connectivity between VPCs without using public internet, VPNs, or Direct Connect. The vendor exposes their RDS database as an endpoint service via a Network Load Balancer (NLB), and the company creates a VPC endpoint to access it. This meets the requirement for private access without an internet gateway, Direct Connect, or Site-to-Site VPN. VPC peering requires non-overlapping CIDR blocks and does not inherently provide private access across accounts without additional networking like VPN or Direct Connect if the accounts are not within the same organization or if specific network configurations are not met. Client VPN is for connecting individual clients to a VPC, not VPC-to-VPC integration. AWS Hosted Connection Direct Connect requires Direct Connect, which is explicitly ruled out. AWS Transit Gateway is for connecting multiple VPCs and on-premises networks, but it still requires a connection method like VPN or Direct Connect to bridge between separate AWS accounts if PrivateLink isn't used for the specific service.