When Mexico became a part of NAFTA, along with Canada and the United States, it:
A. Eliminated traiffs against Canada and the United States but maintained them against nonmembers
B. Eliminated traiffs against Canada, the United States, and all nonmember countries
C. Increasedtraiffs against Canada the United States, and all nonmember countries
D. Increased traiffs against Canada and the United States, but did not change them against nonmember countries