A company enforces CloudTrail across multiple AWS accounts using AWS Organizations. CloudTrail logs are delivered to a centralized S3 bucket that has S3 Versioning enabled. An S3 Lifecycle policy deletes current object versions after 3 years. After year four, the bucket’s total number of objects keeps rising even though new log delivery remains constant. Which solution will most cost-effectively delete objects older than 3 years?

The S3 bucket has versioning enabled, meaning that when an object is updated or deleted, a new version is created, and the old version is retained as a "previous version." The existing lifecycle policy only deletes current object versions after 3 years. This explains why the total number of objects keeps rising: previous versions are accumulating. To cost-effectively delete objects older than 3 years, the S3 Lifecycle policy needs to be updated to include rules for deleting previous versions as well as current versions. This is a native S3 feature, making it the most cost-effective and efficient solution. Configuring the CloudTrail trail to expire objects is not an S3 lifecycle management feature. An AWS Lambda function would incur additional operational overhead and cost compared to a native S3 lifecycle policy. Configuring the parent account as the owner of objects doesn't address the versioning accumulation problem.