Step 1: Match the definition to a word. The phrase describes bringing a buried feeling back to the surface and letting it discharge by re-experiencing the event that buried it. The single psychiatric word for this is abreaction.
Step 2: Mechanism of action. Clinically, abreaction is triggered by methods that lower the censor of the conscious mind, chiefly hypnosis and direct suggestion, allowing the repressed affect to surface and dissipate.
Step 3: Eliminate the rest. Regression means retreating to childlike behaviour under stress, and dissociation means detaching memories or identity from awareness. Because both differ from emotional discharge, the all-of-the-above option fails as well.
\[\boxed{\text{Abreaction}}\]