Explain Gradle Build Types vs. Product Flavors

This question tests your understanding of Gradle's build matrix for separating build concerns from product variations. A strong answer first defines build types for lifecycle stages (debug/release) controlling signing and optimization. Then, it defines product flavors for user-facing versions (free/paid) controlling features and resources. Finally, it explains that build variants are the resulting combinations. A common red flag is suggesting a build type to control something like an API endpoint, which is better handled by a flavor.