The correct answer to this open question is the following.
Although the question is incomplete and does not provide any reference to any text or other options, we can say that point the boy is making when he talks about Christmas trees is that humans must be more sensible about the trees because they are sentient beings.
The idea expressed by the boy was that if Christmas trees were people and people were Christmas trees, then people would be chopped down, put up in the living room as decorations. The trees instead, would be opening our presents. And of course, this resulted in annoying for the people who were listening. This is taken from the story "The Phantom Tollbooth," written by Norton Juster.