Which of the following does not accurately describe transistors?
a. both npn and pnp transistors consist of a base composed of an n-type material.
b. both npn and pnp transistors consist of p-type and n-type material.
c. both npn and pnp transistors operate in the same manner but with interchanged terminals and opposite directions of voltage and current.
d. both npn and pnp transistors consist of an emitter, base, and collector.