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
Trochlear nerve nucleus lies at the level of 
Select and explain. 
A. Inferior cerebellar peduncle, B. Inferior colliculus, C. Superior colliculus, D. Superior cerebellar peduncle
B: Inferior colliculus
Answer: B: Inferior colliculus 
Explanation: Trochlear nerve nucleus is located in anterior part of gray matter that surrounds cerebral aqueduct, at the level of inferior colliculus.