A solid of revolution is generated when a plane area is revolved about a line on its plane. To determine the volume of the solid generated, a differential area dA is drawn. If dA is parallel to the axis of revolution, the method of_ _ is used. O Cylindrical Shell O Disk Rings O Washer Question 38 2 pts The integral expression for the area of the region bounded by the curves y = 20 - 3x2, and y = e" between x = 0 and x = 2 is of2 (ex - 20 - 3x2) dx 12 (20 - ex - 3x2) of2 (20 - ex - 3x?) da of (20 - e" + 3x]) dx