During the Cretaceous Period There Was Globally Very High Sea

During the Cretaceous Period there was globally very high sea level at a time of overall warm climates.What is the mechanism for creating this high sea level?

A) very high rates of seafloor spreading at mid-ocean ridges
B) the polar ice caps melted in the warm climate
C) high rates of comet impacts which melted and added water to the oceans
D) the water was displaced by the bodies of huge marine reptiles