The ornamental design for a chair, as shown and described.
FIG. 1 is a front elevation view of a chair showing my design;
FIG. 2 is a rear elevation view of the chair;
FIG. 3 is a right side elevation view of the chair;
FIG. 4 is a left side elevation view of the chair;
FIG. 5 is a top plan view of the chair;
FIG. 6 is a bottom plan view of the chair; and,
FIG. 7 is a cross-sectional view of the chair, taken along section lines “7-7” shown in FIG. 1.
Throughout the Figures, the dashed broken lines are included for the purpose of illustrating environment of the design and form no part of the claimed design, and the dot-dash broken lines represent boundaries of the claimed design and form no part of the claimed design.