Which Amazon EC2 instance type should the company use to meet these requirements?

Explanations:

On-Demand Instances allow for flexibility and scalability, making them ideal for short-term spikes in traffic. They can be launched or terminated as needed, ensuring the application remains uninterrupted during traffic increases without any long-term commitment or upfront costs.

Spot Instances offer lower costs but are not guaranteed to be available when needed, which could lead to interruptions during traffic spikes. They are subject to termination if the spot price exceeds the user’s bid, making them less suitable for applications requiring uninterrupted service.

Reserved Instances require a long-term commitment (1 or 3 years) and do not provide the flexibility needed for a short-term spike in traffic. While they offer lower pricing compared to On-Demand Instances, they do not meet the requirement for flexibility and immediate scalability.

Dedicated Hosts are physical servers dedicated to a single customer, which may offer greater control and compliance but are typically more expensive and less flexible for short-term spikes. They are not ideal for minimizing costs or maximizing flexibility in the context of sudden traffic increases.