Multiple-choice meta-reactions:

A) This is nonsense. Yes, the social construct of 'mental health' obviously excludes those who are deeply disturbed by the social status quo. Of course there is a strong correlation between having a low opinion of the people around you and being depressed, but simply adopting a rosier view of the world at best cures only the symptom.

B) Wow, this is great! I love it when scientific studies can provide insight into things we intuit but have trouble putting into words. I've always thought this, and it feels great to see others confirming my ideas. I can't wait to read the full paper, but until then I'll remind myself that a positive outlook will help both me and those around me.

C) Both A and B.