Comprehensive and Detailed Explanation (paraphrased from AWS Solutions Architect guidance):

Amazon Route 53 latency-based routing is specifically designed to route users to the endpoint that provides the lowest latency, based on actual latency measurements between AWS Regions and users’ networks. This directly supports the goal of optimizing load times (performance).

For non-AWS endpoints (like an on-premises data center), Route 53 lets you create a latency routing record and associate it with the AWS Region that is closest to that endpoint. In this case, the on-premises data center is near us-west-1, so you associate that latency record with the us-west-1 Region.

Users for whom the eu-central-1 Region has lower latency will be routed to the AWS website in eu-central-1.

Users for whom the us-west-1–associated endpoint has lower latency will be routed to the on-premises website.

This matches AWS best practices for high-performance, low-latency architectures when you have multiple endpoints in different geographic locations, including a mix of AWS and on-premises resources.

Why the other options are not correct:

Option A (Failover routing):

Failover routing is designed for high availability and disaster recovery (active–passive), not for optimizing latency.

All traffic goes to the primary endpoint (eu-central-1) unless it is unhealthy. That does not choose the lowest-latency endpoint for each user, so it does not meet the “optimize load times as much as possible” requirement.

Option B (IP-based routing):

IP-based / geo-based policies are about directing users based on location information (IP/geo), not measured latency.

You would have to manually decide which IP ranges get which endpoint, which does not guarantee that each user goes to the lowest-latency endpoint. It’s less precise and less dynamic than latency-based routing.

Option D (Weighted routing):

Weighted routing splits traffic according to fixed weights (e.g., 50/50), regardless of user location or latency.

This is useful for testing, blue/green deployment, or gradual traffic shifting, but not for performance optimization per user.

Therefore, the only option that directly aligns with AWS guidance for performance optimization and latency-based traffic steering across Regions and on-premises endpoints is:

✅ C. Create a DNS record with a latency-based routing policy… associate the on-premises endpoint with us-west-1.