Identification of candidate BSSs in the field of the SMC. The gray dashed line indicates the zero-age MS isochrone, and the azure dashed vertical line marks the color of the MS turnoff. The blue and red solid line represent the fiducial sequence of MS stars shifted blueward by five times the color error and the equal-mass binary fiducial, respectively. The azure-shaded area indicates region C, and region D is shown in gray. Candidate BSSs are highlighted with blue triangles, and field stars are shown as azure star symbols. See the main text for details.