Respuesta :
"When our lives cease to be inward and private, conversation degenerates to becomeĀ mere gossip". The correct answer is D.
I believe the answer is: D. mere Gossip
From this quote, Thoreau wants to mention that we could never truly know the private life of other people ( like how they think, or why precisely cause a certain even in their life) , which is why if we talk about other people private life, it is closer than a gossip rather than factual information.