Final answer:
Based on sources 2, 3, and 5, a historian would conclude that progressive historians believed in the betterment of people and society, but only on a European model, and viewed history as a straight line to a specific destination.
Step-by-step explanation:
Based on sources 2, 3, and 5, a historian would most likely conclude that progressive historians believed in the betterment of people and society, but only on a European model. These sources suggest that progressive historians viewed history as a straight line to a specific destination, with societies becoming more democratic over time. They also indicate that teleological history was a common perspective among progressive historians, which proposes that history is moving towards a particular end.