The ornamental design for a clamp, as shown and described.
FIG. 1 is a front perspective view of the clamp of the present invention showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a side elevation view thereof;
FIG. 5 is an opposite side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof;
FIG. 8 is a front perspective view of the clamp in FIG. 1 with the jaws in an opened position; and,
FIG. 9 is a rear perspective view of the clamp of FIG. 1 with the jaws in an opened position.
The broken line showing of parts of the drawings is included for the purpose of illustrating use and environment and forms no part of the claimed design.