Which of the Following Mass Extinction Events Is Correct

Multiple Choice

Which of the following mass extinction events is correct?

A) During the Permian period over 90% of the species disappeared due to an excess of carbon dioxide in the atmosphere.
B) At the end of the Ordovician period over 90% of the species went extinct due to a bolide impacting the Earth's surface and causing a cloud of ash to reduce solar exposure for several weeks.
C) At the end of the Cretaceous period over 90% of the species went extinct due to a bolide impacting the Earth's surface and causing a cloud of ash to reduce solar exposure for several weeks.
D) At the end of the Devonian period 70% of the terrestrial vertebrates went extinct when Gondwana drifted back towards the South Pole.