Final answer:
The contrast highlighted is Progressive spirit vs. ethnocentric, showing differing authorial responses to societal changes through the lens of the Progressive movement and social Darwinism.
Step-by-step explanation:
The contrast between the authors revealed in summarizing the passages is A) Progressive spirit vs. ethnocentric. The passages suggest a divergence in perspectives: one group of writers, aligned with the Progressive movement, focused on assessing societal developments critically, as seen in the works of Sinclair Lewis, who satirized middle-class America, and Edith Wharton, who reminisced about the life of the old elite. On the other side, authors influenced by social Darwinism viewed cultural shifts as natural outcomes in a society structured by competitive survival. This dichotomy represents differing responses to the cultural and societal transformations of the time.