Comparison between optical and X-ray LCs, examples of the GRBs in each group. Group A: GRB 080607 (blue/light blue). Group B: GRB 061121 (red/orange). Group C: GRB 060607A (purple/magenta). For each panel: Top. Colored points: X-ray data. The data in light color and bright color represent the continuum and the flaring portions, respectively, as calculated by M 13. Gray dashed lines: X-ray break times. Gray points: optical data. Black solid line: fit to the data. Gray solid lines: components of the fit function used to fit the optical data. Hashed gray boxes: SED time intervals. Middle. Ratio between the optical data and their fit function. Bottom. Ratio between the fit to the X-ray continuum and the optical LC. See Figs. C.1–C.9 for the other GRBs of our sample.