Which of the following represents a well-written basic research problem?

A. How does the organization of mathematical information in long term memory differ between a 3 year old and 13 year old?

B. How do business teams of six or few members compare to teams of more than six members in terms of productivity?

C. Which general education course is more interesting is more interesting, US history or World Music?

D. What is the ratio of native born students to international students on the campuses of major US state universities?