During the Alaskan Gold Rush thousands of mostly nameless<span> men sought their fortune in a harsh environment and lost</span>
Unluckily, you missed to show her the choices in which we can choose our answers from. However, it must be noted that for oral presentation, one must be very knowledgeable about the topic at hand and be able to present it well by being confident in front of the audience.
The coordinating conjuctions in English are just three "and, or, but". 'And' is used to add information, 'or' to indicate alternatives, and 'but' to express contrast. These conjuctions link only units of the same level/ status, for example independent clauses.
1° sentence: Carlos put his books in his backpack, and he walked to the library. Here 'and' is appropiate because you need to add information.
2° sentence: My sister loves dogs but my brother prefers cats. 'But' is the correct one to indicate contrast between the two people's preferences.
3° sentence: Dad will make spaghetti for dinner or he will take us out for pizza. 'Or' is the correct one since the independent sentences signal alternatives
