that's a hard guess to make because
a) she's orange
b) that picture has had the levels/contrast/etc. messed with in photoshop or a similar program
c) it may be a shadow. :/
omega e/s and a little bit of fling eyebrow pencil would probably be your best bet for something that would match that hair colour. but like shimmer said, it's hard to tell exactly because the photo's been altered.