Sentence 4 about year round schooling helps students learn and retain more seems not to be backed up with the evidence and that it may just be a supposition as a better approach might be to coampare the pros and cons of each and at least include the importance of students having a break to rest their brains as constant schooling could become oppressive.
Answer: C) Organic farming preserves soil health and yields more nutrient-rich foods than conventional farming.
Explanation: The article makes a few comparisons that develop an analysis of how each method is different from one another. However, it mainly emphasizes the essential characteristic of Organic farming, which is how soil's natural components and conditions provide a richer harvest than conventional farming does.
I whould say A I could be wrong but I think I am right if you feel I am messing with you can report me.