Answer: On-Demand Instances

## Explanation **On-Demand Instances** are the most cost-effective choice for this scenario because: - **Short-term usage**: The instances are only needed for exactly 1 month with no long-term requirement - **No upfront commitment**: On-Demand instances don't require any upfront payment or long-term contract - **Continuous availability**: Unlike Spot Instances, On-Demand instances won't be interrupted - **Cost comparison**: - **Reserved Instances** require 1-3 year commitments and upfront payments, which are not cost-effective for just 1 month - **Dedicated Hosts** are physical servers dedicated to your use, typically more expensive and require longer commitments - **Spot Instances** are cheaper but can be interrupted with little notice, making them unsuitable for continuous quality assurance tests For short-term, predictable workloads where continuous availability is required, On-Demand instances provide the best balance of cost and reliability without long-term commitments.

Author: Ritesh Yadav