Which of the following does  notaccurately describe transistors?                 a.  both npn and pnp transistors consist of an emitter, base, and collector.      b.  both npn and pnp transistors consist of a base composed of an n-type material.      c.  both npn and pnp transistors consist of p-type and n-type material.      d.  both npn and pnp transistors operate in the same manner but with interchanged terminals and opposite directions of voltage and current.