Excluding themselves from an activity they normally love
I believe this would be foods containing high amounts of sodium, these are the foods that one should eat less of.
A/C/D: All of these answers are positive effects, of human water use.
By process of elimination it must be (B) Also the run off is basically stripping the soil of the nutrients a farmer would need to grow crops, so this is incredibly bad - but a problem easily fixed.
Rowing helps develop muscle endurance. Hope this helps