In the beginning of the story, Taylor is amazed of woods and nature. There is a little sadness as she looks at the tree because she knows, she won't see this tree as a whole again, since it has been split by lightning. However, in the middle of story, Taylor is more focused on the bird; she is afraid of the bird and its beak that could "rip the nose of her face", but still concerned about it and interested in it as well. At the end, she becomes lost and frightened, as she doesn't have the idea where she is.
The answer is d. This sentence helps you separate the actual warning and the word "warning" by using a colon. The other sentences don't make sense because they don't have that.
