Varun's response includes a relevant example of implementing a text-to-speech engine with a base class for scalability, which is a good start. However, the explanation is somewhat unclear and incomplete, particularly regarding maintainability. Varun could improve by discussing specific design patterns, testing strategies, and deployment practices that contribute to both scalability and maintainability, as well as how regular code reviews and refactoring play a role in the long-term health of the system, as outlined in the benchmark response.