Which feature of Unity is used to optimize a game for different platforms?

The feature that is primarily used to optimize a game for different platforms in Unity is the Build Settings. This option allows developers to select the specific platform they want to target, such as iOS, Android, Windows, or Console systems. By adjusting the settings within the Build Settings, developers can enable or disable certain features, choose the appropriate graphics API, and set the platform-specific configurations that can significantly enhance the game's performance and compatibility on the selected platform.

This capability is crucial because different platforms may have varying hardware capabilities and performance characteristics. By using the Build Settings effectively, developers can ensure that their games run smoothly across all intended devices while leveraging platform-specific optimizations.

In contrast, other settings like Quality Settings focus more on graphical fidelity and performance within Unity rather than specifically tailoring the game for different platforms. Player Settings deal with configurations related to how the game behaves on a given platform, and Graphics Settings mainly concern the visual aspects, but they do not provide the comprehensive cross-platform optimization that the Build Settings facilitate.