. , Acompany estimates that it will sell N(x) units of a product after spending $x thousand on advertising. as given by . N(x) : 0.25x4 + 23x? _ 540x2 + 83,000, where 24 s xs 45. When is the rate of change of sales increasing and when is it decreasing? What is the point of diminishing returns and the maximum rate of change of sales? Graph N and N' on the same coordinate system. i The rate of change of sales is increasing on [:11 (Type your answer in interval notation.) The rate of change of sales is decreasing on E. (Type your answer in interval notation.) The point of diminishing returns is D thousand dollars. The maximum rate of change of sales is D sales per thousand dollars. (Round to the nearest whole number as needed.) Graph N and N' on the same coordinate system. Choose the correct answer below. 0 A. I O B. __ 7 O D