Hello !
I think the answer would be...
The last option, "The Nation has to go through significant changes to avoid such tragic wars in the future."
I hope I was able to help you out ! :DD
An example of reinforcement would be a mother gives her son praise (reinforcing stimulus) for doing homework (behavior). The little boy receives $5.00 (reinforcing stimulus) for every A he earns on his report card (behavior).
Not too sure but i think it’s d or b