The correct answer is - B. Improvements to shipping technology.
The globalization process is essentially a process by which the economies have become more open towards one another, and the trade between most of the countries in the world is much easier. The biggest reason for that, apart for the diplomacy, has been the improvement of the shipping technologies which made all of that possible.
With the advancement of the technology, the shipping has significantly improved, became much faster, quicker, and safer, so it made the globalization possible as we see it now.