Which Amazon EC2 pricing model is the MOST cost efficient for an uninterruptible workload that runs once a year for 24 hours?

Explanations:

On-Demand Instances are most cost-efficient for rare, short-term, uninterruptible workloads like this, as they provide flexibility and no commitment for single-day use.

Reserved Instances offer discounts but require a commitment (1 or 3 years), which isn’t cost-effective for a workload running only once per year.

Spot Instances are cheaper but can be interrupted at any time, which is unsuitable for uninterruptible workloads.

Dedicated Instances provide physical isolation and are costly, making them inefficient for a single-day annual workload.