What's the answer to this? i've seen so many different answers.

D) South Korea.

The United States and New Zealand are developed nations, for their GDP is high and consistent.
Ethiopia, is a developing nation, as it's GDP is relatively lower than a developed nation (US, Britian, etc).
South Korea, while it is technically a developed nation, is rising quickly, for it's industries are growing (much like the US's industrial age). Therefore, it is classified as a advanced developed nation.

hope this helps

The correct answer to this open question is the following.

Although there are no options or further references attached we can say the following.

According to Wilhelm II, the "means" and characteristics that were most important for the German Empire to succeed were that the different states had the goodwill to work together and trust each other to get a much-needed agreement, leaving behind personal political agendas and interests, in order to create the German Confederation of the 39 states on order to strengthen their economies in a time when there were many rivalries and enemies in Europe,

This German Confederation was the result of the negotiations during the Congress of Viena of 1815.

Unfortunately, as it was a time of so much rivalry, the German Confederation only lasted until 1848 due to the many political and economic differences between Prussia and Austria. Some years of turmoil would follow after this break until diplomats could improve things in 1866 with the creation of the North German Confederation.