As x values increase, the values of f of x decrease. But this is not a calculus-based justification. So I am going to rule this one out as well. F prime is negative when x is greater than three. Well, that's exactly what I wrote up here. If f prime is negative, then that means that our slope of the tangent line of our original function f is going to be downward sloping, or that our function is decreasing. So this one is looking good.