The ornamental design for a boot, as shown and described.
FIG. 1 is a front perspective view of a boot showing my boot design;
FIG. 2 is a left side view of the boot shown in FIG. 1;
FIG. 3 is a right side view of the boot shown in FIG. 1;
FIG. 4 is a front view of the boot shown in FIG. 1;
FIG. 5 is a left side view of an alternative embodiment of the boot shown in FIG. 1; and,
FIG. 6 is a right side view of the alternative embodiment of the boot shown in FIG. 5.
The broken line showing of the bottom portion of the boot, top rim of the boot, zipper, zipper track, and roping knots is for illustrative purposes only and forms no part of the claimed design.