Was the killing of Archduke Ferdinand , a pivotal reason for World War I starting , so to speak ?
it was the excuse the european government's were looking for.
It was act that started war officially, but I believe reasons were more complicated than that.
Yes it was Most likely the cause of the 1st World War.
The assassination of Archduke Franz Ferdinand of Austria-Hungary in Sarajevo was the spark that set off the war.
Yes. It was one of the major reasons why WW1 started.
That incident triggered the war.