A historian is researching how jazz music evolved in the United States in the early twentieth century as a result of the intermingling of African American and European music traditions. Which two works by other historians will the historian most likely use to develop a hypothesis on this topic?
A) a research paper by a social historian that describes and analyzes African American pop culture in the early twentieth century
B) a research paper by an economic historian that presents evidence showing a huge difference in the income levels of African Americans and white Americans in the early twentieth century
C) a research paper by an economic historian that presents evidence that a high percentage of African Americans were uneducated and jobless in the early twentieth century
D) a research paper by a cultural historian that analyzes different jazz styles and how they developed