One cause of the outbreak of World War I was caused by

Question

1:The outbreak of the Russian Revolution

2:Rising tensions among European powers

3:The killing of a Serbian National

4:The invasion by Germany of Belgium

Answer 1

I think it's 3

Answer 2

https://www.google.com/search?q=immediate+cause+of+WWO&oq=immediate+cause+of+WWO&aqs=chrome..69i57.4954j0j7&sourceid=chrome&ie=UTF-8

Let us know if you change your mind or not.

Answer 3

I changed my mind. I now realize it is 2.

Answer 4

Right.