Explanation:

A simple closed curve is a shape that starts and ends at the same point, without any self-intersections. It can be formed by connecting different points, but it cannot have any gaps or openings.

Polygon:
A polygon is a closed figure made up of line segments, where each line segment intersects exactly two others. It is formed by connecting three or more points in a specific order. Examples of polygons include triangles, squares, and pentagons.

Triangle:
A triangle is a polygon with three sides and three angles. It is a simple closed curve because it starts and ends at the same point and has no gaps or openings. Therefore, a triangle is a simple closed curve and a polygon.

Circle:
A circle is a curved shape that is completely round and has no corners or edges. It is formed by a set of points that are equidistant from a fixed center point. A circle is a simple closed curve because it starts and ends at the same point (the circumference) and has no gaps or openings. However, it is not a polygon because it does not consist of line segments connected at vertices. The curve of a circle is smooth and continuous.

Cone:
A cone is a three-dimensional shape that has a circular base and tapers to a point called the apex or vertex. It is not a simple closed curve because it is not a two-dimensional shape. A cone has a curved surface that cannot be represented by a single closed curve.

Conclusion:
Among the given options, only the circle (option B) is a simple closed curve but not a polygon. It is a closed curve that starts and ends at the same point and has no gaps or openings, but it is not a polygon because it does not consist of line segments connected at vertices.

A circle is a simple closed curve because it has no sharp corners or self-intersections, but it is not a polygon because it doesn't have straight sides.