You will use Azure Functions to process events from Azure Event Hubs. Individual request processing is expected to take between five and twenty minutes. The hosting solution must support estimates of request processing runtimes and provide event-driven autoscaling. Which Functions hosting plan should you recommend?

The Premium (Functions Premium plan) is the best choice because it offers event-driven autoscaling and supports longer runtimes, which are crucial for the 5-20 minute processing window. It also provides pre-warmed instances to avoid cold starts, ensuring consistent performance for event processing. The Consumption plan is unsuitable because it has a maximum execution duration of 10 minutes by default (configurable up to 60 minutes, but not ideal for consistent long-running tasks). The Dedicated (App Service plan) offers custom runtimes but lacks inherent event-driven autoscaling for Azure Functions, requiring manual scaling or custom autoscaling rules. An App Service Environment is an isolated and highly scalable environment but is an overkill for this scenario and more complex to manage, not primarily designed for cost-effective, event-driven function processing.