Find an Approximation of the Area of the Region R

Multiple Choice

Find an approximation of the area of the region R under the graph of the function f on the interval [a, b]. Use n subintervals and choose the representative points as indicated. ​ ; [1, 3]; ; right end points
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A) 6.06 sq units;
B) 5.57 sq units;
C) 5.2 sq units;
D) 5.7 sq units;