B is correct as a Henry reaction. C isn't, though, because there's no nitro compound.
With the alpha carbon of a nitrile acting as the nucleophile, I'd consider B a Knoevenagel condensation, which is a more general class...B & C are both Knoevenagel condensations, but only B is also a Henry. Perhaps there is also a special name when a nitrile is used, but I'm not familiar with one.
I like named reactions...they're very useful and convenient. When someone says they used the Huang-Minlon modification of the Wolff-Kishner reaction, I get a very good idea of what they did.
That said, I hope you also recognize the similarities between the reactions in your list. Try not to lose sight of the forest for the trees.