You are working as an AWS Architect for a media firm. The firm has large text files that need to be converted into audio files. They are using S3 buckets to store this text files.
AWS Batch is used to process these files along with Amazon Polly. For the compute environment, you have a mix of EC2 On-Demand & Spot instances. Critical Jobs are required to be completed quickly, while non-critical Jobs can be scheduled during non-peak hours. While using AWS Batch, management wants a cost-effective solution with no performance impact. Which of the following Job Queue can be selected to meet this requirement?

Answer options:

A.Create single Job Queue with EC2 On Demand instance having higher priority & Spot Instance having lower priority.
B.Create multiple Job Queues with one Queue having EC2 On Demand instance & having higher priority while another queue having Spot Instance & lower priority.
C.Create multiple Job Queues with one Queue having EC2 On Demand instance & having lower priority while another queue having Spot Instance & higher priority.
D.Create single Job Queue with EC2 On Demand instance having lower priority & Spot Instance having higher priority.

Correct Answer – B
You can create multiple Job queues with different priority & mapped Compute environments to each Job queue. When Job queues are mapped to the same compute environment, queues with higher priority are evaluated first.
Option A is incorrect as Multiple queues need to be created for each Job type. In the requirement, critical Jobs will be processed using EC2 instance while low priority jobs will be using Job queue with Spot Instance. 
Option C is incorrect as Priority for a Job queue is selected in descending order. Higher priority Job queue is preferred first.
Option D is incorrect as Multiple queues need to be created for each Job type. In the requirement, critical Jobs will be processed using EC2 instance while low priority jobs will be using Job queue with Spot Instance. Also, a higher priority Job queue is preferred first.
For more information on Job queues in AWS Batch, refer to the following URL-
https://docs.aws.amazon.com/batch/latest/userguide/job_queue_parameters.html