In which stories does the protagonist sell their soul for unlimited knowledge?

The choice referring to Dr. Faustus and Faust is correct because both stories revolve around the theme of a protagonist's pact with a supernatural entity in exchange for knowledge or power. In Christopher Marlowe's "Doctor Faustus," the main character, Faustus, is a scholar who becomes dissatisfied with the limits of traditional forms of knowledge and seeks to gain unlimited knowledge and power. He makes a deal with the devil, trading his soul for 24 years of magical abilities and the acquisition of knowledge beyond human limits.

Similarly, Goethe's "Faust" also portrays a protagonist, Heinrich Faust, who is a scholar that deeply desires to understand the meaning of life and to transcend the human experience. He too makes a pact with Mephistopheles, trading his soul for knowledge and experience. Both works explore the consequences of seeking knowledge at any cost, leading to a downfall that illustrates the dangers of overreaching ambition and the moral implications of such trades.

In contrast, the other options do not involve characters that explicitly sell their souls for knowledge in the same manner. "The Old Man and the Sea" and "Moby Dick" focus more on themes of human struggle and the relationship with nature, while "Romeo and Juliet" and "