One of the Strongest Lines of Evidence of a Meteor

Multiple Choice

One of the strongest lines of evidence of a meteor or comet impact in the late Cretaceous is

A) the extinction of the dinosaurs in only South America.
B) a thin layer of potassium-40 in late Cretaceous fossil strata.
C) a thin layer of iridium-enriched clay in late Cretaceous fossil strata.
D) the warming of Earth's climate in the late Cretaceous.