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 30 year old manic patient was prescribed haloperidol one week back. For the last two days, he has become restless and kept pacing in the room for a day. On examination, he was found to have tremors of hand. He is most likely suffering from - 
Select and explain. 
A. Anhedonia, B. Dystonia, C. Restless leg syndrome, D. Akathisia
D: Akathisia
Answer: D: Akathisia 
Explanation: Restlessness and pacing in room within 1 week of antipsychotic (haloperidol) therapy suggest the diagnosis of Akathisia.