Who do you think is responsible for the first world war?

The war broke out on the 4th of August 1914 and would last until the 11th of November. It was a war between the Great Powers of Europe who were divided into The Central Powers (Germany, Austria-Hungary, and Italy) and The Entente Powers (Great Britain, France, and Russia). Eventually, countries such as the USA joined in. This war was significant as it was the greatest war fought with 30 nations resulting in 8,5million casualties and 21 million wounded. Rivalries between countries, arguments over empires, an arms race are the causes of the European tensions that lead to the war.
In this essay, I will focus on what I think the main cause of World War 1 were.

A cause thought to of sparked the war was the shooting of Archduke Franz Ferdinand, next in line to the Austria-Hungarian throne, by a Serbian terrorist in Sarajevo. This event was, however, simply the trigger that set off declarations of war. This cause is only a short-term cause and perhaps not the actual cause. But on the other side it is one of the main causes, because it is an example of Nationalism.

There are also some long-time causes which I think are real causes to the World War 1.
An example of this is:

Nationalism, is a main cause of the World War 1.
It means to think your country is the best so you will die for it, which is confident, boastful, and chauvinistic. It leads to anger, hatred and rivalry. War becomes the only acceptable solution to a problem. E.g. The war was started when a Serb nationalist assassinated Archduke Franz Ferdinand in Sarajevo in 1914. Also, many Slavs in the area wanted to be free from Austrian rule and rushed to help the other side.
Nationalism was a big cause of the World War 1.
It led to Imperialism as a country believes they are superior to others, they feel they have the right to rule it.

Imperialism is another cause of World War 1.
Imperialism means the desire to built a great empire by ruling and conquering other countries (colonies), which is powerful, and proud. It led to competition, rivalry, and tension. E.g. By 1900 The British Empire extended over five continents and France had control of a large areas of Africa. With the rise of industrialism countries needed new markets.
Imperialism can also cause Militarism as countries dash over colonies they may need to build a navy or army to protect their interests.

Militarism is also another cause of WW1, it means the desire to have a great army, which is for protection, defence and trade. It can lead countries to become more aggressive as they are prepared to wage war.
E.g. The Schlieffen Plan 1905, count von Schlieffen who was a German general devised a plan which prevented the army from being split if attacked from 2 fronts (Eastern+Western). They planned to attack France by