The ornamental design for a carton, substantially as shown and described.
FIG. 1 is a front elevational view of a carton showing my new design, the
back of the carton being of substantially the same configuration and
unadorned;
FIG. 2 is an elevational view looking from the right side of FIG. 1;
FIG. 3 is an elevational view looking from the left side of FIG. 1;