Which of the following sequences of events are most accurate?

Assassination of Franz Ferdinand > Austro-Hungarian ultimatum > Serbian refusal > declaration of war.
Austro-Hungarian ultimatum > Assassination of Franz Ferdinand > Serbian refusal > declaration of war.
Declaration of war > assassination of Franz Ferdinand > Austro-Hungarian ultimatum > Serbian refusal.
None of the above.

The most accurate sequence of events is:

Assassination of Franz Ferdinand > Austro-Hungarian ultimatum > Serbian refusal > declaration of war.