Center of the Sphere is a fixed point in its interior which is equidistant from each point on sphere. Option 1 is not right because it says center is line segment. Option 3 is right as it says it is fixed and equidistant from point of surface.
Step-by-step explanation:
1 The center of a sphere is
2 a line segment from the center point to the surface of the sphere.
3 a fixed point equidistant from all points on the surface of the sphere.
4 a three-dimensional circle in which all points are equidistant from a fixed point.
