The ornamental design for baby bottle, as shown and described.
FIG. 1 is a front elevational view of a baby bottle, showing my new design,
the broken line showing of the nipple and cap is for illustrative purposes
only and forms no part of the claimed design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a left side elevational view thereof,
FIG. 4 is a right side elevational view thereof; and