The ornamental design for a boot (school), as shown and described.
FIG. 1 is a front perspective view of a boot showing my new design;
FIG. 2 is a right side view thereof;
FIG. 3 is a left side view thereof; and,
FIG. 4 is a front view of the boot shown in FIG. 1.
The broken line showing of the heel, tie end, bow portion, and center stitching is for illustrative purposes only and forms no part of the claimed design.