Correlation between observed frequency ν_QPO and the transition radius r_J (top), as well as the residuals defined as the ratio between the best weighted fit (in red) and the data (bottom). In their own colors, different types of quasi-periodic oscillations: Type A in light-yellow, Type B in cyan, Type C in dark-blue. In red the weighed linear fit considering only Type C LFQPOs, , in black ν_QPO = ν_K(r_J)/100, and in dashed-black ν_QPO = ν_ep(r_J)/100.