Which Amazon EC2 pricing model provides the MOST cost savings for an always-up, right-sized database server running for a project that will last 1 year?

Explanations:

On-Demand Instances allow you to pay for compute capacity by the hour or second, but they are typically more expensive over a longer term compared to reserved options.

Convertible Reserved Instances provide flexibility to change the instance type, but they are generally more expensive than Standard Reserved Instances and are not the most cost-effective choice for a long-term, always-on server.

Spot Instances can offer significant savings but are not suitable for an always-up server as they can be interrupted at any time, making them unreliable for consistent use.

Standard Reserved Instances offer significant cost savings (up to 75% compared to On-Demand pricing) when you commit to using EC2 for a year, making them the best choice for a long-term, always-on database server.