The ornamental design for a bassinet, as shown and described.
FIG. 1 is a first perspective view of a bassinet showing my new design;
FIG. 2 is a second perspective view thereof;
FIG. 3 is a perspective bottom view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a right rear perspective view thereof, but shown in the folded position with the handle removed;
FIG. 6 is a left rear perspective view thereof; and,
FIG. 7 is a bottom perspective view thereof.
Broken-line disclosure is understood to represent portions of the article in which the claimed design is embodied, but which form no part of the claimed design.