5冊

The passage presents specific details, and comparing them with the choices confirms that "5冊" is the only accurate representation of the text. This is directly supported by the sentence "・学生（中学生・高校生）：5冊まで、2週間". To solve info-retrieval or detail-oriented questions, scanning for keywords from the question and mapping them to the options is key. As mentioned in the original explanation, According to the library rules, students (which includes junior high and high school students) are allowed to borrow up to 5 books at a time. The other choices, such as "3冊" and "10冊", introduce incorrect facts or make assumptions unsupported by the passage.

本文の「・学生（中学生・高校生）：5冊まで、2週間」という具体的な説明から、正しい内容は「5冊」であることが分かります。このため、本文の記述と一致する「5冊」が正解となります。他の選択肢である「3冊」、「10冊」、「2冊」は、本文の記述と食い違っているか、無関係な情報を述べているためすべて不正解です。