Inaon One commonly used measure of ination is the annual rate of change of the Consumer Price Index (CPI). A TV new story says that the annual rate of change of the CPI is increasing. Check all of the following that must be true. C] The graph of CPI is concave upward. C] The derivative of CPI is negative. C] The graph of CPI is concave downward. C] The second derivative of CPI is positive. C] The second derivative of CPI is negative. C] The derivative of CPI is positive. Question 4 Diminishing Returns Jesaki Inc estimates that it will sell N(3:) units of product after spending $9: thousand on advertising. as given by N(a:) = 0.58 x4+ 46 33 1,097 32+ 157,899. What is the point of diminishing returns? Round to the nearest dollar. $