Bebras 2021 - Level 3 Question 2

With the colour festival approaching, the residents of Colour City decide to repaint their houses in one of three colours: blue (B), red (R) and green (G). They agree on a rule: no house may have the same colour as a neighbouring house or the house directly opposite it across the street. The picture below shows some houses that have already been painted.



Which colours can the beaver’s house be painted to satisfy these conditions?