I don't like the diagram example because it looks like B is being given some form of precedence over C. The lack of symmetry throws me off.
I would suggest having it round in both directions and removing the bottom edge of the 'triangle', so that it looks more like a curly brace. I'm not sure though, that might look weird or too cute.
I agree it definitely looks as though B comes first and then C is a secondary option. Furthermore, I see nothing wrong with the other diagram that doesn't have a curvy path. I think this example is different because it's a three path node. It doesn't jar the mind as badly as a two path node having a sharp vertex.
I would suggest having it round in both directions and removing the bottom edge of the 'triangle', so that it looks more like a curly brace. I'm not sure though, that might look weird or too cute.