Question

Why did many European nations quickly join World War I following the assassination of Archduke Ferdinand in 1914?

Answer 1

B.) They had pledged to fight with other countries.

Step-by-step explanation:

took the test on edge

Answer 2

Because of existing alliances that caused them to be obliged to join forces with which ever side the country they were aligned with joined. This led to a domino affect as one country joined and then it's allied country's joined it on the side it had joined.