Which action should the solutions architect take to accomplish this?
Generate presigned URLs for the files.
Use cross-Region replication to all Regions.
Use the geoproximity feature of Amazon Route 53.
Use Amazon CloudFront with the S3 bucket as its origin.
Explanations:
Generating presigned URLs is primarily for secure, temporary access to S3 objects, not for efficient global distribution.
Cross-Region replication is for data redundancy and availability, not for optimizing access speed for millions of users.
The geoproximity feature of Route 53 helps route users based on their geographic location but does not directly address static content delivery.
Amazon CloudFront is a content delivery network (CDN) that caches content at edge locations, providing fast access to static HTML pages globally.
As I understand it, the answer is:
Use Amazon CloudFront with the S3 bucket as its origin.