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: Anatomy
Which of the following statement is true about left phrenic nerve? 
Select and explain. 
A. Lies anterior to anterior scalenus muscle, B. Posterior to brachial plexus, C. Posterior to subclan aery, D. Posterior to hilum left lung
A: Lies anterior to anterior scalenus muscle
Answer: A: Lies anterior to anterior scalenus muscle 
Explanation: The phrenic nerve arises from the neck from the anterior rami of the 3rd, 4th and 5th cervical nerves. It is formed at the lateral border of the scalenus anterior, opposite the middle of the sternocleidomastoid at the level of the upper border of the thyroid cailage. Phrenic nerve (C3-C5) courses veically along the anterior scalene muscle between the subclan aery and the subclan vein en route to innervate the diaphragm. It is related anteriorly toPreveebral fasciaInf. belly of omohyoidTransverse cervical aerySuprascapular aeryInternal jugular veinSternocleidomastoid musThoracic duct on left sideRef: Moon D.A., Foreman K.B., Albeine K.H. (2011). Chapter 25. Overview of the Neck. In D.A. Moon, K.B. Foreman, K.H. Albeine (Eds), The Big Picture: Gross Anatomy.