In Doping Semiconductor Materials

In doping semiconductor materials,

A) the energy gap between the valence band and the conduction band is completely removed and a covalent bond is formed.
B) impurities are added that either provide extra electrons, or 'holes' for electrons to move through.
C) a large flow of electricity is added to the material kicking electrons out of the material and creating 'holes'.
D) the material is destroyed using an acid.
E) the material is dissolved in an organic solvent.