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: Pharmacology
A 40 year old adult man on medication for psychiatric illness for the last 2 weeks, suddenly develops marked rigidity, immobility, fever, fluetuating BP and hea rate. Most likely diagnosis ? 
Select and explain. 
A. Akathisia, B. Parkinsonism, C. Malignant neuroleptic syndrome, D. Catatonic schizophrenia
C: Malignant neuroleptic syndrome
Answer: C: Malignant neuroleptic syndrome 
Explanation: Ans. is 'c' i.e., Neuroleptic malignant syndrome