Which of the following statements accurately describes AAC's efficiency compared to some formats?

• A. They are lossless and always smaller than MP3.
• B. They deliver high-quality audio but can have large file sizes.
• C. They are best for short clips due to tiny file sizes.
• D. They are not suitable for Apple devices.

Answer: (B)

AAC is a lossy compression method designed to deliver good sound quality at relatively low bitrates, meaning it aims to be efficient by giving you high quality without needing huge files. But the file size you end up with depends on the bitrate you choose. If you encode at a high bitrate to squeeze out the best possible quality, the resulting files can be large. So AAC can provide high-quality audio efficiently, yet, in some encoding settings, the file sizes can be large. The other statements aren’t correct: AAC isn’t lossless, it isn’t defined by being the best option only for short clips, and it is supported by Apple devices.