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
All of the following from the floor of the third ventricle, Except- 
Select and explain. 
A. Infundibulum, B. Oculomotor nerve, C. Mammillary body, D. Optic chiasma
B: Oculomotor nerve
Answer: B: Oculomotor nerve 
Explanation: Ans-B