The ornamental design for a cap, as shown and described.
FIG. 1 is a perspective view of the cap as viewed from in front and from the right, showing the design;
FIG. 2 is a front elevational view of the second embodiment;
FIG. 3 is a right elevational view of the cap, with the left elevational view being a mirror image of the right elevational view;
FIG. 4 is a rear elevational view of the cap;
FIG. 5 is a top plan view of the cap; and,
FIG. 6 is a bottom plan view of the cap.
The portions of the drawings shown in broken lines, including stitching along edges of panels, air vents around the center of the crown, and an oval-shaped area at each side flap are for the purpose of illustrating environmental matter and form no part of the claimed design.