Version A Aside from it being a 9 and 7, i’m not sure what else it could be. It is recognizable though and a cool looking design.
Version C is also nice. Easily identifiable. The only issue I have is the way the corner point of the top right of the 7 doesn’t blend with the 9 like Version D sort of does. Perhaps adding a curve to that corner in Version C would be cool. (Don’t forget the inner corner of the 7 for a curve as well)