I claim ornamental design for a sock, as shown and described.
FIG. 1 is a perspective view of a sock according to the present invention;
FIG. 2 is another perspective view of the sock of FIG. 1;
FIG. 3 is another perspective view of the sock of FIG. 1;
FIG. 4 is a bottom perspective view of the sock of FIG. 1;
FIG. 5 is a front perspective view of the sock of FIG. 1;
FIG. 6 is another front perspective view of the sock of FIG. 1;
FIG. 7 is a front elevation view of the sock of FIG. 1;
FIG. 8 is a rear elevation view of the sock of FIG. 1;
FIG. 9 is a left-side elevation view of the sock of FIG. 1;
FIG. 10 is a right-side elevation view of the sock of FIG. 1;
FIG. 11 is a top plan view of the sock of FIG. 1; and
FIG. 12 is a bottom plan view of the sock of FIG. 1.
The portions of the hand and foot shown in broken lines are for environmental purposes and form no part of the claimed design. The broken lines on the sock represent portions of the sock that form no part of the claimed design.