The right answer is Convection.
Convection is one of three modes of heat transfer with conduction and radiation. The term convection refers to the heat transfer occurring between a surface and a moving fluid when these are at different temperatures. In addition to the energy transfer due to diffusion, there is also transfer through the movement of the fluid. The latter is associated with the fact that multiple molecules have a collective motion, which implies a heat transfer in the case where there is a thermal gradient.