It really depends on the time period.
In modern day diplomacy, it's considered an act of inhumanity to push forward in the name of nationalism. Nationalism is looked at with the same disgust as communism is.
In the 20th century however, nationalism was running rampant. There are the obvious contenders, like Hitler and Mussolini, but nationalism was found in tens of countries at the time. Revolts across South America instilled nationalist regimes, and Japan conquered China in the name of ethnic superiority.
During the times of the French revolution, nationalism was a fetus in the scale of war justifications. Spanish colonies, like Venezuela, were just beginning to recognize themselves as a country instead of a Spanish colony. The United States was just born out of a pretty close war with Great Britain, and Haitian people were beginning to realize that they should not have to live their lives in slavery. The independence of many nations in the New World were justified by nationalism.
The correct answer in this case is that A - They all had agricultural economies.
The reason why this is so is because having a big civilization brings a demand for a lot of food with it. This is something all of the civilizations shared between each other. All of them were big and required a lot of food to be able to sustain themselves - and supplying a civilization with big amounts of food was most easily done by agriculture.
Canada has the 10th (nominal) or 15th-largest (PPP) economy in the world (measured in US dollars at market exchange rates), is one of the world's wealthiest nations, and is a member of the Organization for Economic Co-operation and Development (OECD) andGroup of Seven (G7). As with other developed nations, the Canadian economy is dominated by the service industry, which employs about three quarters of Canadians.[17] Canada is unusual among developed countries in the importance of the primary sector, with the logging and oil industries being two of Canada's most important. Canada also has a sizable manufacturing sector, based in Central Canada, with the automobile industryand aircraft industry being especially important. With a long coastline, Canada has the 8th largest commercial fishing and seafood industry in the world.[18][19]Canada is one of the global leaders of the entertainment software industry.[20]
They opposed it because of the high casualty rate.