Answer:
D) The gas has the same temperature throughout
Step-by-step explanation:
In case of heat transfer due to convection we will say that thermal energy is transferred by the movement of the molecules itself.
Here we know that in convection mode of heat transfer the molecules which are at high temperature will rise above due to lesser density.
Due to this density difference all the molecules of gas at high temperature moves upwards and heavy particles of gas at low temperature comes down.
In this way the molecules will move along with thermal energy and the energy is transferred by convection method.
But if all the gas molecules comes to same temperature then the heat can not flow as there is no density difference and hence there is no energy transfer through the medium