The correct option is D All of these
All electrical conduction, thermal conduction and malleability can be explained by electron sea model.
If the ends of a bar of metal are connected to a source of electric current, electrons from the external source enter the bar at one end. Free electrons pass through the metal and leave the other end at the same rate. Non-localised or free-electron character of the valence electrons is responsible for the high electrical conductivity of metals.
In thermal conductivity no electrons leave or enter the metal but those in the region being heated gain kinetic energy and transfer this to other electrons.
According to the electron-sea model, If one layer of metal ions is forced across another, perhaps by hammering, the internal structure remains unchanged as the sea of electrons rapidly adjusts to the new situation. The presence of the mobile valence electrons, as well as the non directionality of the binding force between metal ions, account for the malleability.