Final answer:
Jazz being banned in many European countries.
Step-by-step explanation:
The correct answer is d) Jazz being banned in many European countries.
While the popularity of jazz did grow outside the United States during and after World War II due to factors such as the influence of American soldiers stationed abroad, the spread of radio and recordings, and cultural exchange programs, it is important to note that jazz was actually banned in many European countries, which hindered its growth in those regions.