How did the alliance system turn a dispute between two countries into world war i?

Although the imperialism that had been developing for decades the powers involved was the main underlying cause, the trigger for the conflict occurred on June 28, 1914 in Sarajevo with the assassination of Archduke Franz Ferdinand of Austria, at the hands of Gavrilo Princip, a young man Serbian nationalist. This event sparked a diplomatic crisis when Austria-Hungary gave an ultimatum to the Kingdom of Serbia and invoked the various international alliances forged over the previous decades. In a few weeks, all the great European powers were at war and the conflict spread to many other geographical areas.

explanation:

there are two statements that are incorrect.

1. the marshall plan was a lend lease program. it was an economic plan that europe redevelop itself after wwii.

2. einstein didn't really do anything to further the allied cause in building the bomb. he merely sent a letter to fdr telling him (in 1939) that if the united states entered the war, perhaps it would be wise to build the bomb before germany did. i would say this answer is incorrect, but when america entered the war 2 years later, fdr thought it might be a good idea to take einstein's advice.

the 4th choice is definitely so wrong that is likely the single answer of this question