B. and E. marked the downfall of the Inca empire, for obvious reasons. Disease and civil war would obviously kill the empire, and taking an important leader would also mark great chaos within the empire. A. and C. are not to be ignored however, considering that maintaining peaceful relationships with the Spaniards only brought death and chaos to the Aztecs, all from the Spaniards.
I would say America was drawn into the war because of the Zimmerman telegram but the answers you have provided are most likely the weekly programs
I believe it was their trading system that spread.
Answer: B. The storming of the Bastille
Explanation: In the book, "A Human Odyssey volume 2" the text states "As the two sides confronted each other, a musket shot rang out. No one knows who fired it. Then the cannons roared." Sounds pretty familiar. The storming of the Bastille was the beginning of the French Revolution.