Which EC2 pricing option can cause a running instance to be interrupted if AWS capacity becomes temporarily unavailable?

Spot Instances allow you to bid on unused EC2 capacity, offering significant cost savings. However, if AWS needs the capacity back, or if your bid price falls below the current Spot price, your instance will be interrupted with a two-minute warning. This makes them suitable for fault-tolerant workloads. On-Demand Instances are charged by the second with no long-term commitment and no interruptions from AWS. Standard Reserved Instances and Convertible Reserved Instances provide discounted pricing for a one- or three-year commitment, and they guarantee capacity, meaning they are not interrupted due to capacity unavailability.