A. Implement AWS Shield to protect against unencrypted objects stored in S3 buckets.
B. Implement Object access control list (ACL) to deny unencrypted objects from being uploaded to the S3 bucket.
C. Implement Amazon S3 default encryption to make sure that any object being uploaded is encrypted before it is stored.
D. Implement Amazon Inspector to inspect objects uploaded to the S3 bucket to make sure that they are encrypted.
E. Implement S3 bucket policies to deny unencrypted objects from being uploaded to the buckets.