Evolution of the three C II lines of SN 2020zbf from −2.4 to +57 rest-frame days. The telluric absorptions are indicated with lighter gray vertical bands. The spectra have been corrected for extinction. A smoothing has been applied utilizing the Savitzky-Golay filter and the original data are shown in lighter colors. The regions corrected for telluric absorptions are indicated with lighter gray vertical lines. A local linear continuum subtraction and an offset were applied for display purposes. The rest-frame wavelengths of the C II lines are illustrated with dashed vertical lines.