The ornamental design for a cupholder, as shown and described.
FIG. 1 is a first perspective view of a cup holder according to the present invention;
FIG. 2 is a second perspective view of the cup holder of FIG. 1;
FIG. 3 is a front view of the cup holder of FIG. 1;
FIG. 4 is a rear view of the cup holder of FIG. 1;
FIG. 5 is a first side view of the cup holder of FIG. 1;
FIG. 6 is a second side view of the cup holder of FIG. 1;
FIG. 7 is a top view of the cup holder of FIG. 1; and,
FIG. 8 is a bottom view of the cup holder of FIG. 1.
The broken line showing of cross-shaped elements in FIG. 7-8, ribbing, rings and flat surfaces in FIG. 8, rings with 4 extensions of FIG. 7 and rear section in FIGS. 1-8 are included for the purpose of illustrating portions of the article that form no part of the claimed design.