The ocean has _________ main temperature layers​

Correct option is D

The ocean has three main temperature layers:

• Surface layer: The topmost layer
• Thermocline: A transitional layer where the temperature decreases rapidly with depth
• Deep ocean: The deepest and coldest layer 

The thermocline is the transition layer between the warmer surface water and the cooler deep water. The thermocline is usually found around 100–400 meters below the surface and extends several hundred meters down. 

The temperature of the ocean determines its form. If the ocean gets cold enough, it turns to solid ice.