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
Illusion is: September 2007 
Select and explain. 
A. A false unshaken belief not keeping one's sociaocultural background, B. Perception without stimuli, C. Abnormal perception by a sensory misinterpretation of actual stimulus, D. Fear of closed spaces
C: Abnormal perception by a sensory misinterpretation of actual stimulus
Answer: C: Abnormal perception by a sensory misinterpretation of actual stimulus 
Explanation: Ans. C: Abnormal perception by a sensory misinterpretation of actual stimulusIllusion is an abnormal perception caused by a sensory misinterpretation of actual stimulus, sometimes precipitated by strong emotion, e.g. fear provoking a person to imagine they have seen an intruder in the shadows.