question_answer

For transistor action            Base, emitter and collector regions should have similar size and doping concentrations.  The base region must be very thin and lightly doped.  The eimtter-base junction is forward biased and base-collector junction is reverse based.  Both the emitter-base junction as well as the base-collector junction are forward biased.

A)  (3) and (4)

B)  (4) and (1)

C)  (1) and (2)

D)  (2) and (3)