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
A31 year old male, with a mood disorder, on 30 mg of haloperidol and 100 mg of lithium, is brought to the hospital emergency room with a history of acute onset of fever, excessive sweating, confusion, the rigidity of limbs and decreased communication for a day. Examination reveals tachycardia and labile blood pressure and investigations reveal increased CPK enzyme levels and leucocytosis. He is likely to have developed - 
Select and explain. 
A. Lithium toxicity, B. Tardive dyskinesia, C. Neuroleptic malignant syndrome, D. Hypertensive encephalopathy
C: Neuroleptic malignant syndrome
Answer: C: Neuroleptic malignant syndrome 
Explanation: Fever, rigidity, excessive sweating, confusion, autonomic instability (labile BP), tachycardia, increased CPK and leucocytosis, in a patient on antipsychotic (Haloperidol), suggest the diagnosis of the neuroleptic malignant syndrome.