Choice C. Fascism wouldn't have been considered a primary cause of World War 1
Explanation: Here's a brief explanation (acronym) that will allow you to remember some of the main causes of World War 1.
Militarism- countries are upgrading their armies and war machinery
Alliances- countries have "friends" that have promised to help them out in the event of another country declaring war on them (this was a BIG factor for this war- this might help explain as to why the world becoming involved, well at least majority of the world)
Imperialism- countries don't want to miss out on the big race for the acquisition of colonies
Nationalism- some countries are starting to get this adrenaline of national pride running through their veins... or in other words they're becoming extremely proud of their countries which sounds like a nice thing, but it can be dangerous ( just the fact that this was a factor in causing World War 1 speaks enough for itself I guess)