The ornamental design for a sock, as shown and described.
FIG. 1 is a plan view of a sock showing my new design in an in-use configuration; and,
FIG. 2 is a perspective view of the sock of FIG. 1 thereof.
The claim is directed to the shaded area of the sock. The broken lines immediately adjacent to the shaded area represent unclaimed boundaries of the design. The broken lines showing the remainder of the sock are for environmental purposes only and form no part of the claimed design. The unshaded region bounded by broken lines immediately adjacent to the shaded area forms no part of the claimed design. The depicted location and orientation of the illustrated shaded area relative to the broken lines showing the boundary of the sock is for illustrative purposes only and the specific location and orientation of the illustrated shaded area relative to the boundary of the sock form no part of the claimed design.