Tank

FIG. 1 is a perspective view of an embodiment of the claimed design; FIG. 2 is another perspective view of the embodiment of FIG. 1 ; FIG. 3 is a front view of the embodiment of FIG. 1 ; FIG. 4 is a rear view of the embodiment of FIG. 1 ; FIG. 5 is a left side view of the embodiment of FIG. 1 ; FIG. 6 is a right side view of the embodiment of FIG. 1 ; FIG. 7 is a top view of the embodiment of FIG. 1 ; and, FIG. 8 is a bottom view of the embodiment of FIG. 1 . The ornamental design which is claimed is shown in solid lines in the drawings. The broken lines illustrate portions of the Tank and form no part of the claimed design. The unequal dash-dot broken lines define the bounds of the claimed design and form no part of the claimed design.