Which best explains how nationalism cause world war 1?

No option provided
however the rise of nationalism was one of the major causes of ww1
Nationalism embodied a feeling of prestige which fueled the acquisition of colonies and consequently rivalry.  
as this rivalry spread, inter ethnic tensions pitting Austria and Balkan nationalities such as the Bosnian,Croatians, became more tense, culminating in the assassination of Austrian heir, Ferdinand at Sarajevo by a Bosnian student.

Forced the british to retreat