A semiconductor differs from a conductor in that it has

• A. Only one path for the free electrons in the valence band
• B. Only one path for holes in the conduction band
• C. Two paths followed by free electrons and holes, one an ordinary path in the conduction band and the other one an extraordinary path in the valence band, respectively
• D. Two paths followed by free electrons and holes, one an extraordinary path in the conduction band and the other one an ordinary path in valence band, respectively