Let's craft a system resembling Google Forms or SurveyMonkey. Imagine a scenario where users can create surveys composed of various question types (e.g., multiple choice, text input, rating scales). Other users can then respond to these surveys. The system must be robust, extensible, and handle concurrent access gracefully. We need to think about how new question types can be easily added, and how responses can be efficiently stored and retrieved. Consider the need to potentially add reporting features later. The focus is on the core domain model and object-oriented design, not building a full-fledged web application.

Requirements