Read Shedding Light on a Dark Day, by Robin Meriwether. The paragraphs have been numbered to help you identify them more easily.

Shedding Light on a Dark Day, by Robin Meriwether

On May 19, 1780, the skies over New England turned dark in the middle of the day. For more than two hundred years, New England's Dark Day had been shrouded in mystery. Some blamed volcanoes. Some suggested supernatural events. Some claimed it was a sign from the heavens. No one knew for certain what happened. Many thought the mystery would never be solved.

Researchers at the University of Missouri were fascinated by the case. They began examining trees in all surrounding areas. Fire damage in a Canadian forest finally revealed the truth. Scientists looked at burned tree rings and discovered that huge wildfires once raged in the mountains near Ontario. The savage flames created blankets of black smoke. The smoke traveled high into the atmosphere, darkening the New England skies hundreds of miles away.

What is the central idea of this article?
A. No one knew why there was a really dark day in New England.
B. On May 19, 1780, the skies over New England turned dark in the middle of the day. For more than two hundred years, New England's Dark Day had been shrouded in mystery. Researchers at the University of Missouri were fascinated by the case.
C. The mystery lasted for over two hundred years.
D. For over two hundred years, the reason for New England's Dark Day was unknown. Finally, researchers from the University of Missouri discovered that wildfire smoke from Canada rose up to the atmosphere, traveled hundreds of miles, and blotted out the sunlight over New England.