[2.25] vs. [1.71]  −  [2.25]  color magnitude diagram. The early-type star candidates are overplotted by light green crosses. Dark green circles and red triangles represent spectroscopically identified early-type stars and late-type giants, respectively. Most of the candidates have a [1.71]  −  [2.25]  color (almost equivalent to a H − K color) of more than 1.5, suggesting that they suffer from strong (A_K ≳ 2) extinction, and thus they are not foreground sources.