When you take one-quarter of a circle in Quadrant III and rotate it about the x-axis, you create a three-dimensional object.
The quarter circle in Quadrant III includes points where \(x\) is negative and \(y\) is negative, forming a quarter of a circle that looks like a "slice" of the circle in that quadrant. When this quarter circle is rotated about the x-axis, it sweeps out a three-dimensional shape.
The shape that is formed by this rotation is a hemisphere. This is because the rotation creates a half-sphere (or hemisphere), as the circular shape is revolved around the x-axis.
Therefore, the correct answer is:
• a hemisphere