What is the primary purpose of Azure Functions?

The primary purpose of Azure Functions is to create serverless applications that can execute code in response to events without the need for infrastructure management. This service allows developers to focus on writing the code that solves their business problems, while Azure automatically handles the execution environment, scaling, and resource provisioning.

With Azure Functions, you can trigger code to run in response to various events such as changes in data, HTTP requests, timers, or messages from queues. This event-driven architecture is designed to be highly flexible and efficient, making it ideal for building microservices and integrating with other Azure and third-party services. The serverless model means you only pay for the compute time that your function uses, which can lead to cost savings and simplified billing for unpredictable workloads.

The other options do not accurately represent the core functionality of Azure Functions. Hosting virtual machines pertains to traditional infrastructure management, which is contrary to the serverless ethos. The facilitation of manual deployment of resources and management of single-page applications are also outside the scope of what Azure Functions is intended to accomplish, as they focus on more complex resource management and front-end application development, respectively.