1. (1 pt each) Below are 4 graphs, each illustrating a Riemann Sum. (a ) (b) (c) (d) Match the graph above with its Riemann Sum below. 5 Ef ( xi-1) Ax i= 1 i= 1 1=1 2. (2 pts) Consider points C and D. One is the centroid of the shaded region; the other is the average midpoint of n approximativectangles as n -co. Label each point, and briefly explain your choices in the section below right