The ornamental design for a b vent exhausttermination, as shown and described.
FIG. 1 is an upper perspective view of a B vent exhaust termination showing my new design;
FIG. 2 is a lower perspective view of the B vent exhaust termination shown in FIG. 1;
FIG. 3 is a front view of the B vent exhaust termination shown in FIG. 1;
FIG. 4 is a top view of the B vent exhaust termination shown in FIG. 1; and,
FIG. 5 is a bottom view of the B vent exhaust termination shown in FIG. 1.
The rear view, left side view and right side view are the same as shown in FIG. 3.
The structural elements depicted by broken lines in FIG. 5 have been included for the purpose of illustrating portions of the B vent exhaust termination which form no part of the claimed design.