A company wants to use Amazon EC2 instances for a stable production workload that will...

 B is correct because Reserved Instances are the instance purchasing option that offers the most cost-effective way to use Amazon EC2 instances for a stable production workload that will run for 1 year, as they provide significant discounts compared to On-Demand Instances in exchange for a commitment to use a specific amount of computing power for a period of time. A is incorrect because Dedicated Hosts are the instance purchasing option that allows customers to use physical servers that are fully dedicated to their use, which is more expensive and less flexible than Reserved Instances. C is incorrect because On-Demand Instances are the instance purchasing option that allows customers to pay for compute capacity by the hour or second with no long-term commitments, which is more suitable for short-term, variable, and unpredictable workloads. D is incorrect because Spot Instances are the instance purchasing option that allows customers to bid on spare Amazon EC2 computing capacity, which is more suitable for flexible, scalable, and fault-tolerant workloads that can tolerate interruptions.