Your firm has uploaded a large amount of aerial image data to S3. In the past, in your on-premises environment, you used a dedicated group of servers to process this data. You used Rabbit MQ – An open-source messaging system to get job information to the servers. Once processed, the data would go to the tape and be shipped offsite. Your manager told you to stay with the current design and leverage AWS archival storage and messaging services to minimize cost. Which of the following options is correct?

Answer options:

A.Use SQS for passing job messages. Use Cloud Watch alarms to terminate EC2 worker instances when they become idle. Once data is processed, change the storage class of the S3 objects to Reduced Redundancy Storage.
B.Setup Auto-Scaled workers triggered by queue depth that use instances to process messages in SQS. Once data is processed, change the storage class of the S3 objects to Glacier.
C.Setup Auto-Scaled workers triggered by queue depth that use instances to process messages in SQS. Once data is processed, change the storage class of the S3 objects to Reduced Redundancy Storage (RRS).
D.Use SNS to pass the job messages. Use Cloud Watch alarms to terminate worker instances when they become idle. Once data is processed, change the storage class of the S3 object to Glacier.

Answer - B
The most suggestive hint in this question is that it asks you to leverage AWS archival storage and messaging services. Hence, you should look for options Glacier and SQS.
Option A is incorrect because (a) RRS is not an archival storage option, and (b) since auto-scaling is not mentioned, you cannot use CloudWatch alarms to terminate the idle EC2 instances.
Option B is CORRECT because (a) it uses SQS to process the messages, (b) it uses Glacier as the archival storage solution - which is cost-optimized.
Option C is incorrect because RRS is not an archival storage option; instead, use Glacier as it is a low-cost archival solution (cost lower than RRS).
Option D is incorrect as SNS cannot be used to process the messages. It cannot replace the functionality that was getting provided by RabbitMQ.