This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Anatomy
Which of the following represent the commonest variation in the aeries arising from the arch of aoa? 
Select and explain. 
A. Absence of brachiocephalic trunk, B. Left veebral aery arising from the arch, C. Presence of retroesophageal subclan aery, D. left common carotid aery arising from brachiocephalic trunk
D: left common carotid aery arising from brachiocephalic trunk
Answer: D: left common carotid aery arising from brachiocephalic trunk 
Explanation: Most common anomaly of the aoic arch seen in 10-20% individuals is characterized by the origin of the left common carotid aery from the brachiocephalic (innominate) trunk. Other common anomalies include: A four vessel arch with separate origins for the right common carotid and right subclan aeries (2.5%), Origin of the left veebral aery directly from a four vessel aoic arch typically between the ostia of the left common carotid and subclan aeries ( 2.4- 5.8%). Ref: Gray&;s anatomy text book of anatomy BD chaurasia 21st Ed.