Study the interaction of the light rays with the mediums. Classify the medium in each image as being transparent or opaque.

Answer:
a) transparent
b) transparent
c) opaque
Explanation:
In the first one, the light rays go completely through, so it is transparent.
The second one I'm not too sure about. It is refraction so it's going through a different material, but the fact that it went through makes me say transparent.
Last one, the light rays are reflecting off the surface so it's opaque.
Please feel free to correct me if I'm wrong. This is just my understanding