Conduction occurs when thermal energy is transferred by the movement of a waves b molecules c liquids d fluids

B. Molecules.

One molecule gains thermal energy and moves to pass that energy to the next molecule and so on until the body in contact end up gaining temperatures.

Option (B)

Explanation:

Conduction is the process in which the heat is given at the one end of solid and the heat transfer due to the vibration motion of molecules of the solid and the other end of the solid also heated.

Energy taken by the molecules make them to vibrate and give energy to the neighboring molecule. So, energy is transferred by the vibrating motion of molecules.  

increase masses, decrease separation