Why is c wrong? E is correct
i see how you would think it’s C), this option does discredit the conclusion
However, even the author admits their conclusion is a bit shaky: “while it sounds simplistic”
To make their conclusion have more ground to stand on they bring up the research finding
Option E) discredits the research (correlation vs causation), by doing so it completely destroys the conclusion
To add on here, remember we are looking for what is the flaw of the argument, so it must be something said or inferred by the author. The author uses carefully chosen language ‘many people experience problems…’ , ‘more of these individuals should…’, and ‘people who do a lot of outdoor activities tend to…’
Notice the choice of: many, more of these individuals, and tend to.
The author is careful not to project here, and is not saying ALL people.
This is another reason we can say C is wrong because the flaw is not projection here, it is rather more cause and correlation like @Juliette said