Which audio system is correctly used for digital television?

The correct choice is Dolby AC-3. This audio system, also known as Dolby Digital, is specifically designed for use in digital television broadcasts and provides a robust audio experience with support for multi-channel sound. It allows for efficient encoding and decoding of audio signals, which is crucial in the context of digital broadcasts where bandwidth is often limited.

Dolby AC-3 supports up to 5.1 channels, which means it can deliver surround sound audio that enhances the viewing experience for television audiences. This capability is particularly important for delivering immersive sound experiences in films, concerts, and other programming formats designed for television viewing.

While other choices like DTS Digital Sound and Linear PCM are also used in various audio applications, Dolby AC-3 remains the standard for digital television due to its compatibility with the AC-3 codec used in many broadcasting scenarios. Therefore, it stands out as the technically correct choice for digital television audio systems.