The ornamental design for a thermostat, as shown and described.
FIG. 1 is a perspective view of a thermostat of the present design.
FIG. 2 is a front elevation view of the thermostat of FIG. 1.
FIG. 3 is a right side elevation view of the thermostat of FIG. 1.
FIG. 4 is a left side elevation view of the thermostat of FIG. 1.
FIG. 5 is a top plan view of the thermostat of FIG. 1.
FIG. 6 is a bottom plan view of the thermostat of FIG. 1; and,
FIG. 7 is a rear elevation view of the thermostat of FIG. 1.
The broken lines in the drawings are for the purpose of illustrating portions of the thermostat that form no part of the claimed design. Surfaces forming part of the claimed design are defined by shaded surfaces. No claim is made to the texture or surface finish of the embodiments shown in the figures.