PV diagrams on the major (top panel) and minor (bottom panel) axis, respectively. On the x-axis, the angular distance from the centre of the source along the direction fixed by the angle ϕ is reported. On the right y-axis, the velocity along the line of sight (in km s⁻¹) is shown as it appears in the input data cube. On the left, the velocity along the line of sight (in km s⁻¹) is shown, once the systemic velocity (v_sys = 36 ± 10 km s⁻¹) has been subtracted. The data are represented in grey scales with blue contours, while the best fit model is identified by red contours. Upper panel: the blue circles represent the projected best fit rotational velocity at different radial distances from the centre, associated with each ring of the disc. Bottom panel: the signature of the potential outflow associated with Region C (bordered in green; see Sect. 4.3) is clearly visible as an excess of CO emission over 100 km s⁻¹ with an offset of ∼1″ from the centre of the rotation.