Left first Posterior Intercostal vein drains into:

Ans. A. Brachiocephalic veinThe left and right brachiocephalic veins (or innominate veins) in the upper chest are formed by the union of each corresponding internal jugular vein and subclavian vein. This is at the level of the sternoclavicular joint. The left brachiocephalic vein is usually longer than the right. Left first Posterior Intercostal vein drains into left Brachiocephalic vein.