FIG. 1 is a top, front perspective view of a first embodiment of a container base showing my new design;
FIG. 2 is a bottom, rear perspective view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a bottom plan view thereof;
FIG. 5 is a front elevational view thereof;
FIG. 6 is a rear elevational view thereof;
FIG. 7 is a left side elevational view thereof; and
FIG. 8 is a right side elevational view thereof.
FIG. 9 is a top, front perspective view of a second embodiment of a container base showing my new design;
FIG. 10 is a bottom, rear perspective view thereof;
FIG. 11 is a top plan view thereof;
FIG. 12 is a bottom plan view thereof;
FIG. 13 is a front elevational view thereof;
FIG. 14 is a rear elevational view thereof;
FIG. 15 is a left side elevational view thereof; and,
FIG. 16 is a right side elevational view thereof.
Broken lines shown in the drawings represent portions of the container base and form no part of the claimed design.