Final answer:
All options listed, San Francisco's Chinatown, Miami's Little Havana, and the Navajo of the Southwest, are subcultures. None of these are exceptions, therefore, the correct answer is 'none of these above'.
Step-by-step explanation:
A subculture is a smaller cultural group within a larger culture, characterized by a shared set of beliefs, behaviors, and customs that are distinctive from those of the larger culture. Subcultures are diverse and can include ethnic and racial groups, such as San Francisco's Chinatown or Miami's Little Havana, which are united by language, food, and other aspects of heritage. They can also be formed around interests, like professional wrestling or anime, shared experiences, or alternative lifestyles, such as the biker or body modification communities.
In the context of the provided question, all of the given options (San Francisco's Chinatown, Miami's Little Havana, and the Navajo of the Southwest) represent subcultures. Therefore, the answer to the question 'all of the following are examples of a subculture except' would be 'd. none of these above'. Every listed example shares a specific identity within a smaller group that is part of the larger American culture.