A company business intelligence team has a number of reporting applications deployed on EC2 instances in their AWS account. The company data warehouse team has provisioned a new set of database sources using AWS RDS in a different AWS account. What is the optimal solution to achieve secure and reliable connectivity from the business intelligence applications to the new RDS databases?

Answer options:

A.VPC Peering
B.Site-to-site VPN
C.Direct Connect
D.PrivateLink

Answer: A
Option A is CORRECT because VPC peering is used to establish connectivity between two Amazon VPC’s over Amazon’s secure and reliable backbone network.
Option B is incorrect because Site-to-site VPN is not the optimal solution as it requires the creation of VPN gateways.
Option C is incorrect because AWS Direct Connect can be used to establish a secure and private connection between an on-premises network and Amazon VPC over a dedicated line.
Option D is incorrect because PrivateLink endpoints are used to integrate AWS services to Amazon VPC without the use of Internet Gateway
Reference:
https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_VPC.Scenarios.html#USER_VPC.Scenario3
https://docs.aws.amazon.com/vpc/latest/peering/what-is-vpc-peering.html