The correct answer is [A] Conduction. The method of heat transmission in which the particles of the medium do not move is conduction. Conduction involves the transfer of heat through direct contact between particles in a material medium. When one part of a solid object is heated, thermal energy is transferred from the hotter region to the cooler region through collisions between adjacent particles. However, the particles themselves do not undergo significant movement from their positions; rather, it is the energy that is transferred through the material. In contrast, convection involves the movement of fluid particles carrying heat energy, while radiation involves the transfer of heat through electromagnetic waves.