Sink

FIG. 1 is a perspective view of a sink showing our design;

FIG. 2 is a front elevational view;

FIG. 3 is a rear elevational view;

FIG. 4 is a side elevational view;

FIG. 5 is a side elevational view; and,

FIG. 6 is a top plan view.

The broken line disclosures in the view represents portions of a sink in which the claimed design is embodied, but which forms no part of the claimed design.