FIG. 1 is a perspective view of an exterior surface of a rear bumper for an automobile according to my novel design;
FIG. 2 is a frontal view of an exterior surface of a rear bumper for an automobile according to my novel design; and,
FIG. 3 is a left side view of an exterior surface of a rear bumper for an automobile according to my novel design.
The broken lines for illustrative purposes only and form no part of the claimed design.