How does heat transfer through conduction? from the warm object to the cool object
D) from the cool object to the warm object
from the warm object into the air
from the air to the cool object

from the warm object to the cool object

Explanation:

Think of heat as a straight line, and the warmer the object the higher its gradient. Now, if you have cold object is lower in heat energy, the heat energy from the warm object will go down the gradient to the cool object. Note, in conduction, there must a contact between the two objects.