Final answer:
Robert Christgau's exact viewpoint in 1973 on the cultural state of rock is not provided, but rock's impact during the era includes a blend of controversy, profitability, and a challenge to societal norms, illustrating the genre's complexity and importance.
Step-by-step explanation:
In 1973, Robert Christgau did not explicitly write any of the statements A, B, C, or D as the question suggests. Instead, it is important to recognize the broad context of rock and roll during the era. Rock music, which thrived on its association with rebellion and cultural diversity, was seen as both controversial and highly profitable. It was a manifestation of the youthful desire for excitement and identity beyond the conservative norms of the time. Despite resistance from some segments of society, rock and roll played a significant role in blurring racial lines and reflecting the social changes of the 1950s. Christgau, known for his insightful critiques of music, would have been aware of rock's commercialization, cultural relevance, authenticity, and its capacity to unify. However, without a specific quote from him in 1973, we cannot definitively attribute any of the given answers to his opinion at the time.