The ornamental design for a scrub, as shown and described.
FIG. 1 is a front perspective view of scrub showing our design;
FIG. 2 is an exploded front elevational view thereof;
FIG. 3 is an exploded rear elevational view thereof;
FIG. 4 is an exploded left side elevational view thereof;
FIG. 5 is an exploded right side elevational view thereof;
FIG. 6 is an exploded bottom plan view thereof; and,
FIG. 7 is an exploded top plan view thereof.
The broken lines represent a human form in FIG. 1 form no part of the claimed design. The broken lines immediately adjacent to the claimed areas represent the bounds of the claimed design. None of the broken lines form any part of the claimed design.