Final answer:
The major challenge specific to global market research is the ability to recognize and respond to national differences.
Step-by-step explanation:
The major challenge specific to global market research is A) The ability to recognize and respond to national differences. In conducting global market research, it is crucial to understand and adapt to the cultural, economic, and social variations in different countries. This requires a deep understanding of cultural values, consumer behavior, and market trends in each specific market.