The ornamental design for a brassiere, as shown and described.
FIG. 1 is a front elevation view of a brassiere showing my new design; and,
FIG. 2 is a side view of the brassiere shown on a person.
The broken lines showing of a person in FIG. 2 is for the purpose of depicting the brassiere as worn by a user and forms no part of the claimed design.