So that is part, that is part C right over there. Now let's do part D, part D, D. At time t equals zero, biscuits with temperature 100 degrees were removed from an oven. So now we're talking about biscuits. We started with t, now biscuits. The temperature of the biscuits at time t is modeled by a differentiable function B for which it is known that B prime of t is equal to this business right over here. Using the given models at time t equals 10, how much cooler are the biscuits than the t? Well, we know what the temperature of the t is, so we just have to figure out the temperature of the biscuits to figure out how much cooler they are than the t. And to figure out the temperature of the biscuits, we can essentially just use the exact same idea.