AWS AD Connector proxies requests to on-premises AD, not replicate. Option B is wrong because AWS RAM is for sharing resources. Option C is wrong because AWS Transit Gateway is for network connectivity.
Option D is wrong because AWS Directory Service for Microsoft AD is a managed directory, but the requirement is replication, not proxy. The correct answer is AWS AD Connector for directory synchronization, but note: AD Connector does not replicate, it proxies. However, the best option for 'replicate' might be to use AWS Directory Service's two-way trust, but that is not listed.
The question is tricky: AD Connector is for authentication proxy, not replication. Actually, the correct service for replication is AWS Managed Microsoft AD with a trust relationship. But among options, none directly replicate.
However, AD Connector is the closest for authentication purposes. The question says 'replicate data', which might be misinterpreted. Actually, AWS does not replicate Active Directory data; it can create a trust.
For the purpose of this exam, AD Connector is used to allow on-premises users to authenticate to AWS applications. So I'll stick with AD Connector.