D.
This information is important to get a full look at VanGogh's personality. Through this we see that he values sorrow much more than happiness, which gives us insight into why he acted the way he did. It is one thing to say that VanGogh was a negative person, looking at his actions and themes in his art, but by giving us words that he actually said that show just how negative he was, we are able to see this aspect of his character with more support and evidence.