[C/Fe]–[Fe/H] trend based on individual C I lines (as indicated in the plots). Black circles indicate that the C I line in question have not been affected by a telluric line, orange circles mean that the line in question has been located closer than 0.3 Å to a telluric line with a depth weaker than 15% of the continuum, and the red circles mean that the line in question is located closer than 0.3 Å to one of the stronger telluric lines. The telluric lines are marked in Fig. 2. In each plot, we also indicate the median [C/Fe] value and the dispersion in [C/Fe].