Answer:
C. Sources
Step-by-step explanation:
A historian cannot create an argument or reach in a conclusion without the sources. And what is a source? A source is a historic document used to maintain a theory or argument. Depending on the ideological proposition followed by the historian, these sources can change. Today, a historic source can be more than just an old document, and now a historian has many choices such as videos, photographies, music, and the talked history.