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 lady complains of sudden onset breathlessness, anxiety, palpitations and feeling of impending doom. Physical examination is normal. What is the diagnosis? 
Select and explain. 
A. Acute psychosis, B. Anxiety disorder, C. Conversion disorder, D. Panic attack
D: Panic attack
Answer: D: Panic attack 
Explanation: Panic disorder is characterised by discrete episodes of acute anxiety. The onset is usually in the early third decade with often a chronic course. The panic attacks occur recurrently every few days. They may or may not have any underlying generalised anxiety disorder.
The episode is usually sudden in onset, lasts for a few minutes and is characterised by very severe anxiety.