This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Symptoms and signs in psychiatry and classification, Subject name: Psychiatry
All are features of delirium except 
Select and explain. 
A. Confusion, B. Disorientation, C. Hyperactivity, D. Loss of memory
D: Loss of memory
Answer: D: Loss of memory 
Explanation: Delirium is the commonest organic symptom seen in clinical practice Characterised by acute onset, clouding of consciousness, disorientation, asterixis, multifocal myoclonus, occupational delirium, tone and reflex abnormalities (Ref: A sho textbook of psychiatry, Niraj Ahuja, 7th edition, pg no.19)