1.A) Alliances.
In this map you can see in different colors the allied countries that went to war together.
2.D) It was the long term cause of World War I due to the tension it created between countries leading to their military buildup, increased pride in culture, and formation of alliances.
These countries nationalism rose over the times of tension between them, each one felt that he had an unjust treatment from the others and eventually they became allies.