[Eu/Fe] vs. [Fe/H] for the field-star sample and the OC sample. The data are colour-coded by Galactocentric bin, and compared with three curves of a given model, corresponding to the same radial regions and coloured in the same way as the data: inner disc (blue), solar-ring (green), and outer disc (pink). We report only models C and D, since the prescriptions for Eu in models A and B are the same as in model C. Small grey dots stand for the field-star sample. Top: comparison with model C. Bottom: comparison with model D. The error bars for the y-axis are displayed for the OC sample.