What architectural style is characterized by horizontal lines and low pitched roofs?

The architectural style that is characterized by horizontal lines and low pitched roofs is the Prairie School. This movement emerged in the late 19th and early 20th centuries, primarily in the Midwest of the United States, and is closely associated with the work of architect Frank Lloyd Wright. The design principles of the Prairie School emphasize harmony with the surrounding landscape, using low, horizontal structures that blend into their environment. This style often includes wide overhanging eaves, open floor plans, and the integration of nature through large windows.

In contrast, the other architectural styles mentioned do not share these specific characteristics. The International Style is known for its emphasis on volume over mass, reliance on industrial materials, and a lack of ornamentation, which leads to a more vertical aesthetic. Art Deco features bold geometric patterns and elaborate detailing, often with a vertical emphasis rather than horizontal lines. Brutalist architecture typically showcases raw concrete and a stark, rugged appearance that does not emphasize horizontal forms or low roofing. Thus, the Prairie School stands out as the correct answer due to its distinctive use of horizontal lines and low pitched roofs.