The commonest variation in the arteries

The commonest variation in the arteries arising from the arch of aorta is:

1.Absence of brachiocephalic trunk.
2.Left vertebral artery arising from the arch.
3.Left common carotid artery arising from brachiocephalic trunk.
4.Presence of retroesophageal subelavian artery.

Ans. 3   [Ref Gray 38th ed page 1513. 65% Normal pattern > 27 % Left common carotid from brachiocephalic trunk > 2.5 % four major arteries branched separately ]