We claim the ornamental design for a truck, as shown and described.
FIG. 1 is a rendered drawing of a front elevational view of a truck of the present design;
FIG. 2 is a rear elevational view thereof;
FIG. 3 is a right-side elevational view thereof;
FIG. 4 is a left-side elevational view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a top, front, and right-side perspective view thereof.
The bottom view forms no part of the claimed design. The rendered drawings include surface shading that represents contour and not surface ornamentation. The broken line showing of windows and portions of the article is for the purpose of illustrating environmental structure and forms no part of the claimed design.