What Is the Most Likely Cause of the Mass Extinction

What is the most likely cause of the mass extinction that occurred 65 million years ago?

A) The Earth's rotation direction reversed when the north and south magnetic poles reversed.
B) A giant asteroid hit the Earth.
C) Mountain building episodes and other tectonic forces blocked animal migration during times of climate change.
D) Forest fires caused a deficit in global oxygen.
E) An increase in the luminosity of the Sun boiled away the oceans.