Final Answer:
The historian who made the claim that "p and g" represented an example of the US being "progressive" in terms of racial barriers as they provided opportunities for Black individuals in cultural products is William Davis. The correct option is D) William Davis.
Step-by-step explanation:
Identification of the Historian: The correct option is D) William Davis. This choice directly addresses the historian who made the specific claim mentioned in the question.
Claim about "p and g": The statement refers to the assertion made by the historian regarding "p and g" being indicative of the United States' progressiveness in breaking racial barriers within cultural products.
Link to Racial Opportunities: The claim suggests that "p and g" played a role in providing opportunities for Black individuals within cultural products, highlighting a positive aspect of progress in racial inclusion.