What category are Ayu's songs in?

[Apekuz]

I've been polishing my collecting of Ayu mp3s... and I found out that most of them wasn't properly 'tagged'. So I proceed put in the year, album and so on so forth with an mp3 tagger. Until I got to the category part.

That stumped me. I just didn't know what category they were "officially" in. In my mp3s some where rock, some jpop, and some even had 'unique' as the category. Well for now I just categorize them as 'Ayu' (^___^)... but do they have any real category? Are all the songs in one category or does each song has its own?