Select the best answer. For purposes of natural resource ex constitutes the United States? O A. The 50 states and the District of Columbia O B. The 50 states and the District of Columbia and the U.S. Continental shelf. 0 C. The 50 states and the District of Columbia and US possessions. O D. The 50 states, District of Columbia, U.S. Continental shelf, and U.S. Possessions Submit Answers