In April 2010 an oil rig blowout resulted in a major crude oil spill in the Gulf of Mexico. How was the majority of the crude oil cleaned out of the Gulf?

A) Humans collected the oil from the surface of the water and along the coastline.
B) Artificial bioremediation, crude-oil eating microbes were poured into the ocean.
C) Natural bioremediation by microbes already present in the ocean.
D) Both human collection of oil and artificial bioremediation.
E) The crude oil still has not been cleaned up.