Which Amazon EC2 pricing model is the MOST cost efficient for an uninterruptible workload that runs once a year for 24 hours?
A . On-Demand Instances
B . Reserved Instances
C . Spot Instances
D . Dedicated Instances
Answer: A
Explanation:
With On-Demand instances, you pay for compute capacity by the hour or the second depending on which instances you run. No longer-term commitments or upfront payments are needed. You can increase or decrease your compute capacity depending on the demands of your application and only pay the specified per hourly rates for the instance you use.
Reference: https://aws.amazon.com/ec2/pricing/