Final answer:
In darkfield illumination, light is directed into the specimen from C. the side, creating a high-contrast image where bright objects stand out against a dark background.
Step-by-step explanation:
With darkfield illumination, light is directed into the stone from the side. This microscopy technique enhances contrast by using a small opaque disk that blocks light from traveling directly through to the objective lens, instead creating a hollow cone of light that focuses on the specimen. Light that has been refracted or reflected by structures in the specimen reaches the objective lens, allowing bright objects to appear on a dark background and improving the visibility of specimens like live, unstained bacteria.
In darkfield illumination, light is directed into the stone from all directions. The technique involves blocking the light passing through the center of the specimen and allowing only the light passing through the periphery to be diffracted by the sample. This creates enhanced contrast, especially for live, unfixed, and unstained specimens.