This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
false fixed firm beleif that the patient has subjectie ceainity is called as 
Select and explain. 
A. hallucination, B. delusion, C. depresonalization, D. derealization
B: delusion
Answer: B: delusion 
Explanation: * DELUSION - * false fixed firm belief, * subjective ceainity, * compelling counterargument, * impervious to other experiences and * outside socio cultural and educational background it is a disorder of THOUGHT CONTENT Ref.Kaplon and sadock, synopsis of psychiatry, 11 th edition, pg. 195