The correct answer to this open question is the following.
Unfortunately, you forgot to include the model and the diagram to see the layers of the Earth. You also forgot to attach the options for this question.
However, trying to help you we can say the following.
In the diagram, the heat is being transferred by convection.
Models are great ways of representing complex ideas with a simple representation. An example of this is the model below of the layers of the Earth.
In the diagram, we can see planet Earth divided into two halves. On the upper side we can see the core of the planet in the color yellow, and above, the puter core followed by the mantle in the color orange. Then on the upper side, the Astherosphere, and at the very top, the Lithosphere.
When we are talking about heat convection, we mean that heat is transferred by the mass movement of some fluids as is the case of water.