This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid Gland, Subject name: Surgery
[{'content': 'Dancing carotid is seen in: \nSelect and explain. \nA. Thyrotoxicosis, B. Hypothyroidism, C. AV Fistula, D. Blow out carotid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) ThyrotoxicosisRef: Bailey and Love Page 756 /26th edition* Most common manifest of Toxicosis - Sinus Tachycardia* Order of appearance of arrhythmias - Multiple Extrasystoles followed by Paroxysmal atrial tachycardia followed by Paroxysmal Atrial Fibrillation and Persistent Atrial Fibrillation not responding to Digoxin.* Means - Lerman Scratch - Systolic scratch sound heard in 2nd Intercostal Space during expiration* Dancing carotids due to hyperdynamic circulation seen in - Aortic regurgitation and Thyrotoxicosis', 'role': 'assistant'}]