So let's pause the video again and see if you can figure this out again and figure out what expression can we use to solve the problem. The problem being, what is the change in the water's depth during the fourth minute? Alright, so we've just talked about if you're trying to find the change in a value, you could take the integral of the rate function over the appropriate time. So we're talking about during the fourth minute. So we definitely wanna take the integral of the rate function. And we just have to think about the bounds and all of the choices here taking the integral of the rate function. So really the interesting part is during the fourth minute.