Question

Which military action led to the start of World War I?
Germany’s invasion of France
Russia’s invasion of Germany
Austria-Hungary’s invasion of Serbia
Italy’s invasion of Bosnia

Answer 1

It was "Austria-Hungary’s invasion of Serbia" that was one of the military actions that led to the start of World War I, since this was a blatant violation of sovereignty. 

Answer 2

Which military action led to the start of World War I?

Austria-Hungary’s invasion of Serbia

The answer is C :) Yw