This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen and pelvis, Subject name: Anatomy
The diaphragm is formed of all the following except 
Select and explain. 
A. Septum transversum, B. Paraxial mesoderm, C. Pleuroperitoneal membranes, D. Dorsal mesentery of oesophagus
B: Paraxial mesoderm
Answer: B: Paraxial mesoderm 
Explanation: The diaphragm is a dome-shaped muscle forming the paition between the thoraxic and abdominal cavities. It is a chief muscle of respiration. Diaphragm develops from the following sources. They are: Septum transversum forms the central tendon. Pleuroperitoneal membranes form the dorsal paired poion Lateral thoracic wall contributes to the circumferential poion of the diaphragm Dorsal mesentery of oesophagus forms the dorsal unpaired poion. Ref - medscape.com