Histograms of the period ratios P_b/P_c (left panel), P_c/P_d (middle panel) and P_d/P_e (right panel) derived from the semi-major axis posterior PDFs given in Figs. 7 to 10 and adopting 1.51 M_⊙ for the host star mass. These period ratios allow to identify which mean-motion resonances are compatible with the allowable orbits derived from our MCMC analysis. It appears clear that the most compatible mean-motion resonance is 1e:2d:4c:8b.