Hip-hop began as a musical style in the United States decades ago. The Japanese have since developed their own version of hip-hop. This is an example of

A. migration
B. acculturation
C. assimilation
D. cultural diffusion

D. cultural diffusion

The correct answer is D. cultural diffusion.

To determine the correct answer, let's review the options:

A. Migration refers to the movement of people from one place to another. Although there may have been some migration of individuals involved in the development of Japanese hip-hop, this does not capture the broader concept being described.

B. Acculturation refers to the process of adopting or assimilating the culture or beliefs of another group. While this may be partially true, it does not encompass the entire phenomenon described in the question.

C. Assimilation refers to the process of fully integrating into another culture, often adopting the cultural norms and values of that group. In the case of Japanese hip-hop, it is more accurate to say that they have developed their own version while still maintaining their distinct cultural identity, rather than fully assimilating into American hip-hop culture.

D. Cultural diffusion is the spread or sharing of cultural elements from one society to another. In this case, the question describes how hip-hop, which originated in the United States, has influenced and been adopted by the Japanese, resulting in the development of their own unique version of hip-hop. This best fits the description given in the question.

To summarize, the example of the Japanese developing their own version of hip-hop is an illustration of cultural diffusion because it demonstrates the spread and adoption of an American musical style to another society, resulting in a new cultural expression.