The correct answer is their. Because his or her wouldn't make sense because it says they, his also wouldn't make sense for that reason, and the other form of there means for example, "over there"
Not vary relevant to the main plot line of the story
In this article, it shows how The Diary of Anne Frank was taken to North Korean schools and being used to teach hatred for western society in the students by comparing Americans with the Nazis. This article is against this use of such an important book, and supports this by quoting Buddy Elias, Anne's cousin, who was shocked by the government established parallelism between Hitler and Bush, instead of Hitler and <span>Kim Jong-Il.
Therefore, your best answer is </span><span><em>The purpose is to condemn a misuse of the Diary the evidence is that the author includes quotations from Ann's cousin who does not approve the use.</em></span>