Once the powder keg was ignited, what made it difficult to stop the chain of events that led to all-out war in Europe in 1914? Question 5 options:

A. Nations responded to threats to their allies by mobilizing their militaries.

B. The policy of isolationism followed by European nations had been largely ignored by 1914.

C. European leaders believed a war in Europe would revive their struggling economies.

D. A quick, reliable system of communication was not available to foreign ministers.