The ornamental design for ring, as shown and described.
FIG. 1 is a perspective view of a ring, showing my new design;
FIG. 2 is a right side elevational view thereof; the left-side, front and rear elevational views being identical thereto; and,
FIG. 3 is a top plan view thereof; the bottom plan view being identical thereto.
The broken lines shown in the drawings illustrate portions of the ring that form no part of the claimed design. The inner surface of the ring containing surface shading forms part of the claimed design.