For which one of the following does the centre of mass lie outside the body?

The centre of mass (CM) is the unique point where the entire mass of a system can be considered to be concentrated for the purpose of analyzing external forces. While the CM usually lies within the physical boundaries of an object, such as the middle of a cricket ball or a book, it can also lie in empty space outside the material body for certain geometries. For a uniform ring, the mass is distributed along the circumference, but the geometric center is equidistant from all points on the ring. Consequently, the centre of mass of a ring is located at its geometric center, which is a point in the hollow space outside the actual material of the body. In contrast, objects like a fountain pen, a cricket ball, and a book have their mass distributed such that the CM remains within their physical structure.