Let's design a quizzing application where users can take quizzes on various topics. The core idea is to create a flexible and maintainable system that can easily accommodate different question types, scoring mechanisms, and quiz delivery methods. We need to ensure that the design is robust, extensible, and thread-safe, allowing for future enhancements and scalability. Imagine this being used in a classroom, a training environment, or even a casual game setting. The application needs to handle multiple users concurrently taking quizzes without data corruption or race conditions. It should be easy to add new question types or scoring rules without modifying existing code extensively.

Requirements