We claim the ornamental design for a sink, as shown and described.
FIG. 1 is a top, front perspective view of an embodiment of the claimed design;
FIG. 2 is a front elevation view thereof, each of the left, right, and rear elevation views being a mirror image thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a bottom plan view thereof; and,
FIG. 5 is a cross-sectional view taken along Line 5-5 in FIG. 3.
The ornamental design which is claimed is shown in solid lines in the drawings. The broken lines in the drawings form no part of the claimed design. Broken lines formed by equal length dashes show unclaimed subject matter. Broken lines formed of unequal length dashes (i.e., dash-dot) define bounds of the claimed design.