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
I feel like it could be either A or B but im not sure due to the fact that I have no idea what the passage was about and which president we are discussing
The Word Lake is prepositional, so i guess,"Walked alongside the Lake."
Do is a command, in the past instructing.
Does is in the present, currently doing.
