Final answer:
Technological advancements have the greatest impact on defining global business by reducing trade costs and enhancing communication, which in turn influences other factors such as cultural diversity, economic nationalism, and political stability.
Step-by-step explanation:
When considering what is likely to have the greatest impact in defining the field of global business, it's crucial to look at the forces shaping the modern economic landscape. Technological advancements have proven to be a dominant force by reducing costs in trade, enabling the rapid and efficient flow of information, goods, and services, and allowing businesses to operate on a global scale. This, in turn, affects cultural diversity, economic nationalism, and political stability. However, technological advancements stand out as they stimulate and facilitate almost all other aspects of global business including the emergence of new business models, the enhancement of communication and logistics, and the innovation of products and services.
Cultural diversity certainly contributes to framing the global business arena through varied consumer tastes and workforce management strategies. Meanwhile, while economic nationalism might limit global business by prioritizing domestic industries, its overall influence tends to be less pronounced compared to the ubiquitous and transformative power of technology. Political stability is undoubtedly important for consistent business operations, yet it is the technological advancements that often propel a country into greater stability through economic growth and opportunities.