If we follow German Law it´s probably none of the above.
Kölsch is per definition and law a clear golden brew. So not in this category. But as we at Ratebeer call the category Kölsch / Kölsch-Style and have many way too hoppy American Kölsch styles in here it´s okay to put in there.
Schwarzbier is nowadays bottom-fermented, so no Kölsch in here. But looking back in history there have been Schwarzbier that were top-fermented as most of the beers dating back to the middleages and before Louis Pasteur.
I personally would put it to Kölsch-Style and as if we dont already have too many styles this would nee to be splitted to Kölsch - Traditional and Kölsch - Modern/Black.