S1 문장의 [______]에 들어갈 단어는?

난이도 고난도 · 힌트를 덜 열수록 높은 점수 (현재 5점)
Around the turn of the twentieth century, [______] trained in the natural sciences began to reimagine what a science of humanity should look like and how social scientists ought to go about studying cultural groups.