Answer:
I believe the answer here is B. Contamination of drinking water.
Step-by-step explanation:
By process of elimination we can eliminate 3 answers. Decreasing harmful carbon emissions, improving health in livestock, and helping smaller farms stay in business are not consequences, so they are out.
The only other option besides B is breaks in the supply chain, which means production is not going as efficiently. Therefore it really doesn't pertain here because factory farming increases productivity, with bad consequences.
Lastly, contamination is the only option left.
Hope this helps!