The ornamental design for a whisk, as shown and described.
FIG. 1 is a perspective view of a whisk showing our new design;
FIG. 2 is a top view thereof;
FIG. 3 is a section view thereof;
FIG. 4 is an enlarged view of a representative portion of the section view thereof;
FIG. 5 is a back end view thereof;
FIG. 6 is a front end view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a right side view thereof; and,
FIG. 9 is a left side view thereof.
The broken lines shown in the drawings are included for purposes of illustrating handle portions of the whisk and form no part of the claimed design. In FIGS. 1-9, the entire outer surface of each outer loop member that is located adjacent an outer periphery of the disclaimed handle portions all have a shiny surface as depicted by the linear shading on the representative outer loop member in FIG. 4 and are all made of the same material as depicted by the illustrated hatching of representative outer loop member in FIG. 4, while the entire outer surface of each inner loop member that is located closer to the center of the disclaimed handle portions all have a matte surface as depicted by the stipple shading on the representative inner loop member in FIG. 4 and are all made of the same material as depicted by the illustrated hatching of the representative inner loop member in FIG. 4.