The answer is C, Conduction.
The transfer of heat through contact with a solid object is called conduction, as opposed to convection which is transfer of heat through contact with a fluid(gas/liquid).
The question is asking about the heat going through the bowl, so this means your answer is conduction.
Also, osmosis is the movement of a liquid through a semipermeable membrane and radiation is the transfer of energy without direct contact(sunlight, nuclear radiation).
Hope this helped! :)