Amazon EC2 Spot Instances offer the most cost-effective approach to utilizing a significant amount of compute power for tasks that can be interrupted and have flexible start and end times, such as batch processing jobs or background tasks. Given that the company's workload is periodic and occurs at well-defined times, with an ability to handle interruptions (resumption of simulations), Spot Instances provide the required compute capacity at lower costs than On-Demand or Reserved Instances. EC2 Dedicated Hosts are more targeted towards licensing requirements and consistent performance, and T3 instances, while providing burstable performance, may not offer consistent high performance throughout the simulation period, making both of these options less aligned with the company's combination of a high-compute, cost-effective, and periodic processing routine.