Whereas heat transferred between the ocean and the atmosphere occurs more rapidly when the ocean is warmer than the air, it is slow when the ocean is colder.

A. Whereas heat transferred between the ocean and the atmosphere occurs more rapidly when the ocean is warmer than the air, it is slow when the ocean is colder.
B. Unlike the slow process of heat transfer between the ocean and the atmosphere when the ocean is colder than the air, heat transfers more rapidly when the ocean is warmer.
C. The transfer of heat between the ocean and the atmosphere is slow when the ocean is colder than the air and more rapid when the ocean is warmer.
D. Transferring heat between the ocean and the atmosphere occurs slowly when the ocean is colder than the air and more rapidly when it is warmer.
E. When the ocean is colder than the atmosphere, heat transferred between them occurs slowly, unlike the more rapid transfer occurring when the ocean is warmer.

OA C

Source: GMAT Prep