This question is missing the excerpt. I've found it online. It is the following:
He looked out the window at the vast emptiness. He watched the rise and fall of a telephone wire. In his mind he could hear his father's gruff voice softly singing to him.
Answer:
The author reveals details about the character because:
B. He describes Stanley's thoughts when he looks out the bus windows.
Step-by-step explanation:
Even though letter C might be tempting - the author mentions that Stanley is watching a telephone wire move -, letter B is the best choice. It is Stanley's thoughts that reveal something about him. Notice that the author describes his thoughts in a very poetic manner: "In his mind he could hear his father's gruff voice softly singing to him." This is enough for readers to infer there is a loving and important relationship when it comes to Stanley and his father.