What is happening in step 4 of the image below?A. Formation of a surface ocean waveB. Sinking of cooling ocean waterC. Upwelling of warming ocean waterD. Formation of an ocean gyre

The answer to this question is letter C. Upwelling of warming ocean water. In the figure below, step 4 in the thermohaline circulation shows that it is in the Pacific ocean. It is where the deep water surfaces in the process called upwelling.