You would use "sabor" in the context of taste or flavor, but in the context of your options, it appears none of the provided cases directly relate to "sabor." However, if you were specifically asking about knowing in the sense of experiencing something, the closest option could be interpreted in a more general context:
D. to say you know how to play the piano
This option could involve "sabor" if you were referring to having a feel or taste for music, but typically, "sabor" is not used in the context of knowledge like the other options.
In Spanish, "saber" would be more appropriate for knowledge, while "sabor" relates primarily to taste and flavor.