A Company Uses AWS Organizations to Manage One Parent Account

A company uses AWS Organizations to manage one parent account and nine member accounts. The number of member accounts is expected to grow as the business grows. A security engineer has requested consolidation of AWS CloudTrail logs into the parent account for compliance purposes. Existing logs currently stored in Amazon S3 buckets in each individual member account should not be lost. Future member accounts should comply with the logging strategy. Which operationally efficient solution meets these requirements?

A) Create an AWS Lambda function in each member account with a cross-account role. Trigger the Lambda functions when new CloudTrail logs are created and copy the CloudTrail logs to a centralized S3 bucket. Set up an Amazon CloudWatch alarm to alert if CloudTrail is not configured properly.
B) Configure CloudTrail in each member account to deliver log events to a central S3 bucket. Ensure the central S3 bucket policy allows PutObject access from the member accounts. Migrate existing logs to the central S3 bucket. Set up an Amazon CloudWatch alarm to alert if CloudTrail is not configured properly.
C) Configure an organization-level CloudTrail in the parent account to deliver log events to a central S3 bucket. Migrate the existing CloudTrail logs from each member account to the central S3 bucket. Delete the existing CloudTrail and logs in the member accounts.
D) Configure an organization-level CloudTrail in the parent account to deliver log events to a central S3 bucket. Configure CloudTrail in each member account to deliver log events to the central S3 bucket.