Answer: B. Mexico
Explanation: During the 1990s, many U.S. industries began to relocate to Mexico. The reasons for this are many, including lower labor costs, trade agreements, and access to new markets. Mexico's proximity to the United States and its large and growing market made it an attractive destination for U.S. companies. Also, the North American Free Trade Agreement (NAFTA) signed in 1994 between Canada, Mexico, and the United States, made it easier for U.S. companies to invest in Mexico and export their products back to the U.S. market. Panama, Columbia, and San Salvador are different countries but they were not the main destinations for U.S. industries during the 1990s.