If f(x) = g(x), this means the values of the functions are the same when using the same numbers. That means if we use 2 for x, then f(2) would need to be equal to g(2); if we use 0 for x, then f(0) would need to be equal to g(0). This is the case in this option, so this option is correct.
Well this is my opinion I would try to compared both them and see if they have something familiar in their arguments. If not I would try to view their different point of view and write your own opinion about it. I would check out another book about the World War 2 because there's infinite of books about it.