Second option is correct. A cone with open base is formed when the segment is rotated about the axis as shown in figure.
What is solid revolution?
A solid revolution is a three dimensional figure obtained by rotating a two-dimensional figure or (curve) around a straight line(called the axis) that lies in the same plane.
According to the question
If we see in the given figure, there is a triangle about a vertical line. As the triangle is revolved about a line, the vertices A and C remain stationary. While the vertex B which follows the path of circle. As the triangle rotates, AB creates the outline of cone.
Hence, Option second is correct i.e. a cone with an open base.
Learn more about the solid revolution here:
https://brainly.com/question/24201856
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