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: Unknown
Retro pharyngeal space extends up to which of the following level? 
Select and explain. 
A. Base of skull to C6 vertebra, B. Base of skull to bifurcation of trachea, C. Base of skull to the level of diaphragm, D. Base of skull to cricoid cartilage
B: Base of skull to bifurcation of trachea
Answer: B: Base of skull to bifurcation of trachea 
Explanation: (Refer: P. L. Dhingra’s Diseases of Ear, Nose and Throat & Head and Neck Surgery, 6th edition, pg no: 265)