Two identical concave mirrors each of focal length $$f$$ are facing each other as shown in the schematic diagram. The focal length $$f$$ is much larger than the size of the mirrors. A glass slab of thickness $$t$$ and refractive index $$n_0$$ is kept equidistant from the mirrors and perpendicular to their common principal axis. A monochromatic point light source $$S$$ is embedded at the center of the slab on the principal axis, as shown in the schematic diagram. For the image to be formed on $$S$$ itself, which of the following distances between the two mirrors is/are correct: