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 patient presents with one month history of abnormal hallucination and delusion. The patient lacks the insight to his changed behaviour. Likely diagnosis is - 
Select and explain. 
A. Paronia, B. Depression, C. Psychosis, D. Schizophrenia
C: Psychosis
Answer: C: Psychosis 
Explanation: Delusion, hallucinations and lack of insight are features of psychosis.