(Solved): The figure shows four long horizontal layers (identified by the letters A to D) of different materia ...

The figure shows four long horizontal layers (identified by the letters A to D) of different materials, containing air above and below them. The refractive indexes are given in the figure. Light rays fall from the left, as illustrated in the figure. In which layer is the possibility of guiding light (by total reflection), in such a way that after multiple reflections the light comes out on the side layer right? Explain.