The Tenth Question: All or Nothing!

is episode 25 of the original Naruto anime.

Synopsis
The camera moves around and comes to class where the Genin are writing the exam. Ibiki Morino says that incompetent ones have already dropped, so he, after 45 minutes, can give the final, tenth question. But he says that there is one special rule for this question. Meanwhile, the scene moves to the place where Kakashi Hatake, Asuma Sarutobi and Kurenai Yuhi are. Kakashi and Asuma explain to Kurenai that Ibiki is a great ninja, specialized for torture and interrogation.

Back in class, Ibiki says that they can choose whether or not they want to try and solve the tenth question. If they don't want to, the entire team will fail, but if they choose to answer the question but don't know the answer, they will lose the privilege to take the Chūnin Exams forever. Many of them choose not to answer the question and they leave the class. Naruto, in his loud style says: "I'm not scared! I will take this exam!" calming everyone down. After that, Ibiki says that all who remain in the classroom (78 students) pass. He then explains that the meaning of first nine questions were to test their information gathering skills.

As for the tenth question, that was put in to test their determination and bravery. He compares it to a hypothetical ninja mission, in which a group of ninja has to break into an enemy fortress without any information on the enemy, with the high possibility that the enemy is expecting them. The group cannot give up on the mission and fight another day.

After that, through the window crashes the second examiner, Anko Mitarashi. At the end of episode, Ibiki picks up Naruto's exam and smiles, because this was the first time he saw a student pass with an empty exam.