Which type of heat transfer involves the movement of warmed material? a. radiation b. conduction c. convection

The answer they are looking for is Convection, because it is usually applied to one single material, generally in liquid or gas forms, like boiling water, and the heating happens by the heated particles traveling up and taking the place of the cooler ones, that travel down and are heated themselves, and they keep doing this circle until the whole material is warmed.
Actually all three categories of heat transfer involve movement of heat of not movement of warmed material such as it happens in convection.
With conduction the difference is that you touch one warmer object to the another cooler one, they could be of the same kind or different, and the heat of one will travel to the other at the same time as the cool of the other will travel to the one, until they are the same temperature, but you see it’s not the warmed material itself that it’s moving here, it is the heat and the cool. Radiation does not require that the source of heat touch the object to be heated, because it travels through magnetic waves.

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