f(x) million barrels per day 21.2 21.0 20.8 20.6 20.4 20.2 B 20.0 19.8 19.6 2 D F x years since 2000 8 10 (a) List the labeled points in order of increasing steepness. (Enter your answers as a comma-separated list.) (b) Is the graph in the figure concave up, concave down, or neither (an inflection point) at each of the labeled points? A ---Select--- ---Select--- BCDEF ---Select--- ---Select--- C ---Select--- ---Select--- C (c) Should tangent lines lie above, lie below, or cut through the curve at each of the indicated points? JABCDEF ---Select--- B ---Select--- B ---Select--- 9 ---Select--- ---Select--- B ---Select--- B (d) Calculate df dx (Round your answers to one decimal place.) x=4 million barrels per day