The ornamental design for a bra, as shown and described.
FIG. 1 is a front perspective view of a bra showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a right side view thereof; and,
FIG. 5 is a left side view thereof.
The broken line showing of portions of the body of a wearer, and the upper region of the bra, is for illustrative purposes only and forms no part of the claimed design. The broken line above the shaded region forms an unclaimed boundary of the claimed design. The loops on the stripe that encircles the bottom of the bra represent a terry cloth appearance.