The Abundant Remains of Ammonites in Oklahoma Indicate

The abundant remains of ammonites in Oklahoma indicate

A) that Oklahoma was in the past a vast desert with almost no rainfall.
B) that Oklahoma was in the past part of a mountain range that has now eroded.
C) that Oklahoma was in the past covered by a shallow ocean.
D) that Oklahoma was part of a vast tropical forest.
E) that Oklahoma was always a grassland.