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: Ophthalmology
Superior oblique is supplied by: 
Select and explain. 
A. Upper branch of 3rd N, B. Lower branch of 3rd N, C. Trochlear, D. Abducens
C: Trochlear
Answer: C: Trochlear 
Explanation: C i.e. Trocheal nerve