To understand the right answer here, we need to differentiate between facts and opinions. So; opinions are personal conclusions and interpretations. They are not entirely based on definite knowledge. However, facts are proofs in themselves supported by knowledge, articles, or report about the subject.
In this case, the famous "Diary of Anne Frank" is a primary source that presents proofs and personal struggle in some horrific circumstances.
Moreover, the options that are given to choose from, the last two points are both facts that prove to be true and can be crosschecked in reference to the primary source- the diary. But, the first point is an opinion by some student which has clearly no access to such proof. Hence, it becomes obvious that Option-1 is an opinion, not the others.
