Final answer:
The best example of a "differential of contemporaneousness" is capitalizing on 24-hour commodity trading across time zones in the global economy. This leverages the constant state of different time zones to engage in continuous trading, showing the interconnection of global markets facilitated by technology.
Step-by-step explanation:
The concept of a "differential of contemporaneousness" broadly relates to differences in how current or up-to-date various factors are within the global economy. Given the choices provided, the best example of this concept is exhibited by capitalizing on 24-hour commodity trading across time zones in the global economy. This practice leverages the constant state of different time zones to trade commodities around the clock, thereby utilizing the global nature of trade and the technology that enables this incessant trading.
Just in time production and corresponding order fulfillment, which increase efficiency and lower a firm's costs, showcase the synchronization of production schedules with demand. This might be related to a "differential of contemporaneousness" in terms of a firm's supply chain efficiency. However, the more exact example would be the continuous trading across time zones, highlighting the interconnection of global markets facilitated by technological advancements in communications and transportation.
The change over time in costs associated with shipping across international borders illustrates factors contributing to globalization, but this is more about the evolution of costs rather than a differential of being contemporary. Europe's varied adoption of industrialization is a historical process and doesn't quite capture the ongoing, real-time aspect inherent in the term "differential of contemporaneousness."