Until Recent Times, Astronomers Had to Await a Total Solar

Until recent times, astronomers had to await a total solar eclipse to study the chromosphere. Why couldn't an observer hold a coin in front of them to cover the solar disk and create an artificial "eclipse" that would permit them to study the chromosphere?

A) Refraction of light around the coin will cause light from the photosphere to enter the observer's eye along with light from the chromosphere.
B) Light from the very rarified chromosphere is too weak to penetrate Earth's atmosphere.
C) Scattering by Earth's atmosphere will allow light from the photosphere to pass around the coin and enter the observer's eye.
D) Even with electronic equipment, it is not possible to hold the coin steady enough against the apparent motion of the Sun to view only the thin chromosphere.