Final answer:
The answer to the question is D. Babbitt, a novel by Sinclair Lewis that satirizes American middle-class conformity.
Step-by-step explanation:
The novel that satirized the conformity of the American middle class is D. Babbitt. Written by Sinclair Lewis, this work humorously but sharply critiques the pressures and expectations of middle-class life in America during the 1920s. The title character, George F. Babbitt, is a real estate agent who becomes increasingly disillusioned with the materialistic and conformist nature of his society. This novel is seen as a seminal work that explores themes of the American Dream and individualism versus conformity.