A SysOps Administrator manages an application where Amazon EC2 instances in an Auto Scaling group read messages from an Amazon SQS queue. When the message traffic increases, the EC2 instances fall behind, taking too long to process the messages.
How can the administrator configure the application to reduce the latency during traffic spikes?

Answer options:

A.Configure the Auto Scaling group to scale based on a schedule.
B.Trigger scaling events based on the number of messages in the queue.
C.Trigger scaling events based on the disk space used on the EC2 instances.
D.Manually increment the Auto Scaling group’s desired capacity during traffic spikes.

Correct Answer: B
This example is also given in the AWS Documentation.
Since the number of messages is the main component for scaling, that should be used in this case.
For more information on scaling based on SQS, please visit the below URL-
https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-using-sqs-queue.html