Final answer:
Sentence 2 should be modified to have the right tone by adding historical context and a more formal writing style, indicating why the people of Spain preferred chili powder over black pepper.
Step-by-step explanation:
The sentence that should be changed to have the right tone is sentence 2: "When choosing between it and black pepper, they chose chili powder." This sentence seems a bit informal and lacks historical context. A revision maintaining the proper tone and providing a brief context could say, for instance, "Faced with the option of traditional black pepper, the people of Spain developed a preference for the newly introduced chili powder." It is important to maintain a consistent and formal tone in academic writing, especially when discussing historical topics such as the introduction of chili powder to Spain and its preference over black pepper.