This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
A fundamental technique used in psychoanalysis is - 
Select and explain. 
A. Concentration, B. Hypnosis, C. Empathy, D. Free association
D: Free association
Answer: D: Free association 
Explanation: Psychoanalysis is based on the principle of free association, where the patient is asked to say whatever comes to mind.