Which of the Following Was Apparently a Reason for Organized

Which of the following was apparently a reason for organized labor to oppose the North American Free Trade Agreement (NAFTA) ?

A) Lack of environmental and employment safeguards in Mexico
B) Small gaps between U.S.and Canadian wages
C) Concerns regarding a country gaining competitive advantage through higher costs resulting from not attending to worker welfare
D) Small gaps between U.S.and Mexican wages