The ornamental design for a tray, as shown and described.
FIG. 1 is a front perspective view of my ornamental design for a tray;
FIG. 2 is a left side view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a front elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a front exploded view thereof.
In FIG. 8 the dash-dot dash line show the relationship of assembly of the various parts wherein the top part is slightly separated by a distance from the main body of the tray. The other broken line showing of portions of the tray is included for the purpose of illustrating environmental structure and forms no part of the claimed design.