'When an adolescent is unable to show anger to his parents, then he shows his…

Concept: A defence mechanism is an unconscious strategy the mind uses to manage anxiety created by an unacceptable impulse or a threatening situation. Displacement, specifically, works by redirecting an emotional impulse (most often anger or hostility) away from the original threatening target onto a safer, less threatening substitute target.

Application: The adolescent feels anger toward his parents, but expressing it directly toward them is risky (fear of punishment or disapproval). He therefore redirects the same anger onto his younger brother, a target he perceives as safer. The emotion itself does not change; only its target shifts from parents to brother, which is exactly the mechanism of displacement.

Cross-check: Comparing the defining feature of each option against the scenario confirms the choice:

• Repression keeps the threatening impulse out of conscious awareness entirely; here the adolescent is fully aware of his anger and acts on it, so nothing is being kept unconscious.

• Regression means reverting to behaviour typical of an earlier developmental stage (tantrums, clinginess); the scenario describes no such reversion, only a shift of target.

• Projection means attributing one's own unacceptable feeling to someone else, as if that other person holds it; here the adolescent owns and expresses his own anger rather than claiming his brother is angry with him.

• Displacement means the emotion is transferred intact onto a safer substitute target, exactly as described here — anger meant for the parents lands on the younger brother instead.

Since the anger is redirected onto a substitute target rather than being suppressed from awareness, expressed through earlier-stage behaviour, or attributed to someone else, the scenario matches displacement.