Question: "What audio compression formats that are not Vorbis do not contain limitations that are inherent to the mp3 format?"

Context: "There are also open compression formats like Opus and Vorbis that are available free of charge and without any known patent restrictions. Some of the newer audio compression formats, such as AAC, WMA Pro and Vorbis, are free of some limitations inherent to the MP3 format that cannot be overcome by any MP3 encoder."

Answer:
AAC, WMA Pro
The context mentions several audio compression formats that are free of any limitations inherent to the mp3 format. AAC, WMA Pro and Vorbis are three such examples mentioned in the text. So out of these three options, which ones do not contain limitations? The answer is "AAC" and "WMA Pro"..