With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: The leaching of highly water soluble tannins from decaying vegetation and leaves along a stream may produce what is known as a blackwater river. Water flowing out of bogs has a characteristic brown color from dissolved peat tannins. The presence of large amounts of tannins (or humic acid) in well water can make it smell bad or taste bitter, and these effects can serve as a marker for other chemicals that often co-locate with humic acid and can render the water toxic for human consumption.
text_B: Would it be advisable, for health reasons, for a utility to use a dog's sensitive nose to try to detect even a faint odor in drinking water before allowing it to be delivered to houses?
YES.