In an n-p-n transistor
Both emitter-base and collector-base junctions are forward biased
Both emitter-base and collector-base junctions are reverse biased
Emitter base junction is forward biased and collector base junction is reverse biased
Emitter base junction is reverse biased and collector base junction is forward biased
For any transistor emitter base junction has to be forward biased and collector base junction has to be reverse biased.