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
Which of the following term denotes a false sensory perception in the absence of an external stimuli? 
Select and explain. 
A. Delusion, B. Illussion, C. Hallucination, D. Obsession
C: Hallucination
Answer: C: Hallucination 
Explanation: False sensory perception in the absence of an actual external stimuli is a perceptual abnormality called hallucination. Hallucinations are perceived as 'real' by the patient. It can be in different modalities like, sound (auditory), taste (gustatory), touch (tactile), sight (visual), smell (olfactory) and combined (multi-modal hallucinations).Ref: Kaplan & Sadock's Synopsis of Psychiatry: Behavioral Sciences : By Benjamin J Sadock, M.D, Page 244