El Nino, the periodic abnormal warming of the sea surface off Peru, a phenomenon in which changes in the ocean and atmosphere combine allowing the warm water that has accumulated in the western Pacific to flow back to the east.

(A) a phenomenon in which changes in the ocean and atmosphere combine allowing the warm water that has accumulated
(B) a phenomenon where changes in the ocean and atmosphere are combining to allow the warm water that is accumulating
(C) a phenomenon in which ocean and atmosphere changes combine and which allows the warm water that is accumulated
(D) is a phenomenon in which changes in the ocean and atmosphere combine to allow the warm water that has accumulated
(E) is a phenomenon where ocean and atmosphere changes are combining and allow the warm water accumulating