A). when the region is divided into a greater number of rectangles.
Step-by-step explanation:
This forms the basics of integration.
Integration can be use to calculate areas under the curve. To find the area under the curve we try to approximate the area under the curve by using rectangles. When we increased the number of rectangles of equal width of the rectangles, a better approximation of the area is obtained. We then find the area of each infinitesimally small rectangle and then integrate by taking two limits, the upper limit and the lower limit.
