AWS Certified Solutions Architect – Associate (SAA-C03) — Question 88

A company wants to reduce the cost of its existing three-tier web architecture. The web, application, and database servers are running on Amazon EC2 instances for the development, test, and production environments. The EC2 instances average 30% CPU utilization during peak hours and 10% CPU utilization during non-peak hours.
The production EC2 instances run 24 hours a day. The development and test EC2 instances run for at least 8 hours each day. The company plans to implement automation to stop the development and test EC2 instances when they are not in use.
Which EC2 instance purchasing solution will meet the company's requirements MOST cost-effectively?

Answer options

Correct answer: B

Explanation

Option B is the most cost-effective solution since Reserved Instances provide a significant discount for the production EC2 instances that run continuously, while On-Demand Instances are suitable for the development and test environments that have variable usage. Option A, C, and D do not optimize costs effectively for the production environment or do not appropriately address the usage patterns of the development and test instances.