Can't move MP3 audio book from Music to Audiobooks in iTunes
I have an old MP3 audio book in several folders. In the File Explorer folder I right clicked the individual files "Open in iTunes" => In iTunes "Album Info" I marked every file under "Details" Track 1 of 9, 2 of 9 etc.
Under "genre" it automatically shows "Audio book" and artwork shows correctly.
.....however in the "Options" under "Album Info" I can't change it to "Audio book" and it only shows up on my iPhone in the Music.
How can I move the book to Books?
Windows, Windows 10