The ornamental design for a knife, as shown and described.
FIG. 1 is a perspective view of a first embodiment of a knife, showing the new design, lined to show the color of blue;
FIG. 2 is a right side view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is rear view thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a perspective view of a second embodiment identical to the first embodiment of a knife, but all portions that are lined to show the color of blue in the first embodiment are instead lined to show the color of green;
FIG. 9 is a perspective view of a second embodiment identical to the first embodiment of a knife, but all portions that are lined to show the color of blue in the first embodiment are instead lined to show the color of orange; and,
FIG. 10 is a perspective view of a second embodiment identical to the first embodiment of a knife, but all portions that are lined to show the color of blue in the first embodiment are instead lined to show the color of red.
The broken lines shown in the drawings are for illustrative purposes only and form no part of the claimed design.