1). (Melissa's burn). None of the choices is correct.
Heat transferred from her hand to the water by conduction.
2). (Radiator on the walk).
Its heat will not warm the air on the other side of the room.
The radiator will warm the air around it, and THAT warm air will
eventually move to the other side of the room by convection.
3). (Heat transfer by radiation)
That's how heat spreads from a light-bulb.