Answer:
a) heat flows from the warm plate to the cold one
Step-by-step explanation:
Heat is an expression of energy, the bodies with more heat mean that they have more energy. In this way, they can share or pass this "excess" of energy to the cold body. Both plates are not in total contact but some part are close enough (they are touching) that the heat can pass from one to the other. Also the heat always need a media to travel, in this case, the air that surrounds the plates is also the media that the heat travels from the hot to the cold one.