Which of the following is not true? A. You can figure the exact volume of a solid by slicing it into cross- sections, figuring the individual volumes by multiplying cross- sectional area times thickness, and adding them up. O B. In a solid of revolution, the cross-sections are circles or washers. C. A solid of revolution is obtained by revolving a region about a line. D. Figuring the volume of a solid can involve slicing it into cross- sections. O E. You can figure the volume of a solid by slicing it into cross- sections, figuring the individual volumes, and adding them up