A company needs to reduce storage costs. All data is currently in the Amazon S3 Standard storage class. Data must be retained for at least 25 years. Data from the most recent 2 years must be highly available and immediately retrievable. Which solution meets these requirements?

The correct solution uses an S3 Lifecycle policy to transition objects to S3 Glacier Deep Archive after 2 years. This meets the requirement for data from the most recent 2 years to be highly available and immediately retrievable (remaining in S3 Standard), while cost-effectively storing older data for 25 years. S3 Glacier Deep Archive is the lowest-cost storage class for long-term archival. Transitioning immediately to S3 Glacier Deep Archive (option 1) would violate the 2-year immediate retrieval requirement. S3 Intelligent-Tiering (option 3) is designed for unknown or changing access patterns, but it doesn't guarantee immediate transition to Glacier Deep Archive for all data after 2 years, and manual archiving activation isn't the primary mechanism for this specific requirement. Transitioning to S3 One Zone-IA immediately (option 4) would also violate the 2-year immediate retrieval requirement and adds an unnecessary intermediate tier.