Which Organisms Represent the Source of Our Petroleum Oil Products

Which organisms represent the source of our petroleum oil products?

A) The flowering plants that arose during the Cretaceous period
B) The remains of the dinosaurs from the Jurassic period
C) Phytoplankton that first appeared during the Triassic period
D) The remains of the extensive swamp forests from the Carboniferous period
E) The remains of fish from the Devonian period