Read the link to help you with the question, Ensure you are reasonable well informed by reading the Wikipedia article on NAFTA athttp://en.wikipedia.org/wiki/North_American_Free_Trade_Agreement.
Now, What do you think are the main marketing advantages for the United States? Also, the disadvantages? Consider the nation as a whole, consumers and workers. Then do the same for Mexico and Canada. Address the points that you feel are the most important.