Option 1: Corona - The corona refers to the outermost layer of the Sun`s atmosphere and has nothing to do with the darkness of the shadow during an eclipse.
Option 2: Umbra - This is the correct answer. The umbra is the darkest portion of the shadow cast during an eclipse. It is the region where the light source, such as the Sun, is completely blocked by the object causing the shadow, resulting in a complete absence of direct light.
Option 3: Penumbra - The penumbra is the region surrounding the umbra and is partially illuminated. It is less dark than the umbra and shows a partial shadow effect.
Option 4: Black hole - Black holes are astronomical objects with extremely strong gravitational forces that can trap light. However, they are not relevant to the darkness of the shadow cast during an eclipse.
In conclusion, the correct answer is option 2, which is the umbra.