Which of the following best supports the idea that Turner took a positive view of the effects of the frontier on American history?
A. And to study this advance, the men who grew up under these
conditions, and the political, economic, and social results of it, is
to study the really American part of our history.
B. We shall consider the whole frontier belt including the Indian
country and the outer margin of the "settled area of the census
reports.
C. That coarseness and strength combined with acuteness and
inquisitiveness; ... these are traits of the frontier, or traits called
out elsewhere because of the existence of the frontier.
D. Too exclusive attention has been paid by institutional students to
the Germanic origins, too little to the American factors.