The World Wildlife Fund has declared that global
warming, a phenomenon most scientists agree to be
caused by human beings in burning fossil fuels, will
create havoc among migratory birds by altering the
environment in ways harmful to their habitats.
(A) a phenomenon most scientists agree to be
caused by human beings in burning fossil fuels,
(B) a phenomenon most scientists agree that is
caused by fossil fuels burned by human beings,
(C) a phenomenon that most scientists agree is
caused by human beings' burning of fossil fuels,
(D) which most scientists agree on as a phenomenon
caused by human beings who burn fossil fuels,
(E) which most scientists agree to be a
phenomenon caused by fossil fuels burned by
human beings,