Question

During the Ordovician period, it is believed that the sea levels dropped due to the movement of the continents. This event led to the extinction of over 50 percent of all life on earth. This event occurred about A) 5 billion years ago. B) 475 million years ago. C) 450 thousand years ago. Eliminate D) 500 million years ago.

Answer 1

The Ordovician period ended 443.7 million years ago, so i guess the answer choice would be B, as that is the closest to the time span. 
C might be a typo though. i would ask the teacher if it is a typo or not.