Step 1: Understand the "race turn" concept.
The "race turn" refers to a shift in academic and social thought in the USA during the 20th century, focusing on race and racial issues, especially in sociology, literature, and history.
Step 2: Identify the thinkers.
W. E. B. Du Bois was a key figure in the intellectual movement around race in the USA, making him connected to the "race turn."
Alain Locke, known for his work during the Harlem Renaissance, was also deeply involved in issues related to race.
Stuart Hall, although a major figure in cultural studies, is more associated with race studies in the UK, not specifically the American "race turn."
Frederic Jameson, a Marxist theorist, is more focused on class and postmodernism, not race, making him less connected to the "race turn."
Thus, the correct answer is (B) and (C).