Now is that depicted here? When x is equal to one and y is equal to one, our slope isn't negative one, our slope here looks positive. So we can rule this one out. Now let's try the next one. So if x is equal to one and y is equal to one, well then dy dx would be equal to one minus one, or zero. And once again, I just picked x equals one and y equals one for convenience. I could have picked any other.