A start-up firm has enabled AWS CloudTrail in the us-west-1 region delivering all logs to an Amazon S3 bucket in the same region. Recently the firm has expanded to other regions. The security team is looking for CloudTrail logs from all the regions to be delivered to the existing Amazon S3 bucket in the us-west-1 region.
What configuration can be done to meet these requirements in the most efficient way?

Answer options:

A.Configure CloudTrail as the multi-region trail to deliver log files to the Amazon S3 bucket in the us-west-1 region. Ensure CloudTrail has full permissions to the Amazon S3 bucket.
B.Configure CloudTrail as a multi-region trail to deliver log files in the Amazon S3 bucket in each region and then use Cross-region Replication (CRR) to aggregate log files to the Amazon S3 bucket in the us-west-1 region.
C.Configure CloudTrail as the single-region trail to deliver log files in the Amazon S3 bucket in each region and then use Cross-region Replication (CRR) to aggregate log files to the Amazon S3 bucket in the us-west-1 region.
D.Configure CloudTrail as the multi-region trail to deliver log files to the Amazon S3 bucket in the us-west-1 region. Ensure CloudTrail has a write permission to the Amazon S3 bucket.

Correct Answer: D
CloudTrail Trails can be configured as multi-region trails which will log events from all regions. These logs can be delivered to a single Amazon S3 bucket. CloudTrail should have write permission on this Amazon S3 bucket to deliver logs.
Option A is incorrect as full permission is not required. Only write permission is necessary to deliver logs from all regions to an Amazon S3 bucket.
Option B & C are incorrect as although this will work, this will incur additional admin work for configuring replication between the Amazon S3 bucket in each region and the Amazon S3 bucket in the us-west-1 region.
For more information on aggregating log files to a single Amazon S3 bucket, refer to the following URL,
https://docs.aws.amazon.com/awscloudtrail/latest/userguide/receive-cloudtrail-log-files-from-multiple-regions.html