What type of challenges does the society focus on addressing?

The most fitting focus of the Mysterious Benedict Society is on the threats posed by the Whisperer, as this embodies the overarching conflict that drives the narrative. The Whisperer, a nefarious force in the story, represents the challenges the society must confront and overcome, reflecting the themes of courage and strategic thinking. The society members, with their unique skills and talents, come together to combat this threat, which is central to the plot.

While the other options highlight important societal concerns, they do not capture the primary focus of the society's mission in the context of the story. The personal psychological issues, social inequalities, and academic situations are relevant but are not the direct challenges that the society actively addresses through their adventures and teamwork against the Whisperer.