Well, that is a justification for why h is increasing, but that's not calculus-based, and no way are you using a derivative. So, this isn't a calculus-based justification. It's above the x-axis. So, this one, what is it? Are they talking about h? Are they talking about h prime? If they're saying that h prime is above the x-axis when x is greater than zero, then that would be a good answer, but this is just, you know, what is above the x-axis and over what interval?