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,
The correct sentence is c. This is a case of Noun + Noun modifier. A phenomenon is modifying global warning and that clause which immediately follows a phenomenon talks more about the phenomenon.
A is wordy and has a meaning error.
B again has a meaning error, it incorrectly implies that global warming is caused by fossil fuels.
D has the same meaning error. Yes, it is caused by human beings but how it is done by them is not clearly stated.
E is wordy and awkward.
Please comment if my explanation has any error.
Thank you