The ornamental design for a candle, as shown and described.
FIG. 1 is a front elevational view of candle showing my new design, the rear elevational view being a mirror image;
FIG. 2 is a right elevational view, the left elevational view being a mirror image;
FIG. 3 is a top plan view; and,
FIG. 4 is a bottom plan view.
The drawings are lined on the candle for color and on the wick for the surface of the wick respectively. In the drawings, the broken lines depict environmental subject matter only and form no part of the claimed design.