It would be B. An autobiography is a person's story written by THAT person.
I believe there are two sentences in the excerpt that reflect the main character's uneasiness with his family history, and those are:
1. <span>The full contents of the chest never came quite clear, perhaps because he didn't want to know.
</span>2. <span>His mother had once tried to explain the paper to him, but he hadn't wanted to listen.</span>
