Answer:
C. The stratum contains iridium
Explanation:
The Asteroids are large rocky bodies found on the orbit of the sun.If a fragment of a asteroid falls on the earth it is known as the meteorite According to Luis and Walter Alvarez they stated that a huge asteroid strikes the gulf coast of mexico that killed many species o earth including the dinosaurs.this might be the reason for extinction of dinosaurs.Scientists and researchers reported that more than one asteroid involved in extinction of species of the earth.