Final answer:
David Stern is responsible for the emphasis on product extensions and team sport promotional strategies, enhancing the NBA's popularity globally. Therefore, the correct option is D.
Step-by-step explanation:
The emphasis on product extensions and the development of team sport promotional strategy can mainly be attributed to David Stern. Stern was the Commissioner of the National Basketball Association (NBA) from 1984 to 2014, and he is widely credited with increasing the popularity of the NBA on a global scale. His marketing strategies included expanding the NBA's audience through clever use of media rights, merchandising, and the promotion of star players.