The statement that best describes how a historian would use a transcript of this speech is C) As a primary source on Roosevelt's political views.
Explanation: A transcript of this speech by Franklin D Roosevelt would be considered a primary source for historians. Primary sources are original, firsthand documents or records created during or immediately after a historical event. In this case, the speech was given by Roosevelt himself and provides insight into his political views at the time. By analyzing this transcript, historians can gain a better understanding of Roosevelt's beliefs and priorities during his presidency, including his ideas about achievement, creativity, and social responsibility.