Question

Why were alliances a main cause of World War I?

Alliances strengthened demands for self-determination.
Nations were less likely to use diplomacy in settling disputes.
If one nation was attacked, the others would come to its aid.

Answer 1

C. If one nation was attacked, the others would come to its aid.

Step-by-step explanation:

"Protection through Alliances"

" Rising tensions caused European nations to form alliances. The alliances offered nations a feeling of security. If one of the nations of the alliance was attacked, the others would come to its aid. By 1914, two major alliance groups were created."

Answer 2

The right answer is:

If one nation was attacked, the others would come to its aid.

The first two options are generical issues that cannot be proven historically.

On the other hand, the obligation to come in aid of an allied nation was a real factor in the origin of the war, that lasted from 28 of July, 1914, to 11 of November, 1918. The historical reason was the assassination of Archduke Franz Ferdinand, heir of the Austro-hungarian empire, by serbian nationalists.

Because of this incident, Austria-Hungary declared war on Serbia, and shelled its capital, Belgrade.

And after that network of interlocking alliances enlarged the crisis from a bilateral issue in the Balkans to one involving most of Europe, dividing it in two main coalitions: the Triple Entente—consisting of France, Russia and Britain—and the Triple Alliance of Germany, Austria-Hungary and Italy.