Which of the following is a situation that would require using both Spot and Reserved EC2 Instances?

Answer options:

A.A build that has sudden unpredictable workload spikes but for a short time horizon.
B.One in which there is a predictable resource demand over a long time horizon.
C.One that has unpredictable spikes for a long time.
D.One that has a constantly predictable workload with brief unpredictable spikes.

Correct Answer – D
In cases that are characterised by a constantly predictable workload with brief unpredictable spikes, Amazon EC2 Reserved Instances would be the most cost-effective to meet the constantly predictable workload. Whilst Spot Instances in an auto-scaling group would suffice to meet the demands of the build.
https://aws.amazon.com/solutions/case-studies/mercadolibre-ec2/
Option A is INCORRECT because this use case would be cost-effectively serviced by Amazon EC2 Reserved Instances with on-demand instances in an Auto Scaling group to meet the resource demands of the spike.
Option B is INCORRECT because this use case would be cost-effectively serviced by Amazon EC2 Reserved Instances alone.
Option C is INCORRECT because this use case would be cost-effectively serviced by Amazon EC2 On-demand Instances in an Auto Scaling group to meet the resource demands of the spike.