Jeff has been extremely aggressive since childhood. he pursues a career in boxing, which provides a socially acceptable channel to express his aggression. this scenario best illustrates the defense mechanism of

The correct answer to this question is "Sublimation".

Sublimation is a type of behavioral defense mechanism in which what is socially intolerable actions are unconsciously converted into socially tolerable actions later on. Therefore this results in a long-term transformation of the original impulse.