For which use case are Amazon EC2 On-Demand Instances MOST cost-effective?
Compute-intensive video transcoding that can be restarted if necessary
An instance in continual use for 1 month to conduct quality assurance tests
An instance that runs a web server that will run for 1 year
An instance that runs a database that will run for 3 years
Explanations:
Spot Instances would be more cost-effective for compute-intensive tasks that can be interrupted, as they are cheaper but may be reclaimed by AWS.
On-Demand Instances are ideal for short-term, steady usage without long-term commitments, such as a 1-month QA testing period.
Reserved Instances would be more cost-effective for a web server with predictable, long-term use (e.g., 1 year).
Reserved Instances or Savings Plans would be more cost-effective for continuous use over multiple years, as they offer significant discounts for long-term commitments.