The handle of a pot becoming too hot to grab is primarily an example of conduction.
Conduction is the transfer of heat through a material, and in this case, the heat from the pot (which is heated by the stove) is transferred through the material of the pot to the handle. As the pot heats up, the heat energy travels through the metal of the pot and into the handle, making it hot to the touch.
While convection and radiation are also methods of heat transfer, they are not the primary mechanisms at play in this scenario. Convection involves the transfer of heat through the movement of fluids (like air or liquid), and radiation involves the transfer of heat through electromagnetic waves (like heat felt from a fire). In the case of the pot's handle, conduction is the dominant process.