Final answer:
Swift is a programming language used for mobile app development, web development, and game development on Apple platforms.
Step-by-step explanation:
Swift is a programming language developed by Apple for building apps for iOS, macOS, watchOS, and tvOS. It is widely used for mobile app development, allowing developers to create native applications for Apple devices. While it is primarily used for mobile app development, Swift can also be used for web development and game development on the Apple platforms. Therefore, the correct answer is 4) All of the above.