A company has a database server that is always running. The company hosts the server on Amazon EC2 instances. The instance sizes are suitable for the workload. ...

A company has a database server that is always running. The company hosts the server on Amazon EC2 instances. The instance sizes are suitable for the workload. The workload will run for 1 year.
Which EC2 instance purchasing option will meet these requirements MOST cost-effectively?

A. Standard Reserved Instances B. On-Demand Instances C. Spot Instances D. Convertible Reserved Instances