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
Vidian nerve is formed by union of? 
Select and explain. 
A. Superficial petrosal nerve and deep petrosal nerve, B. Greater petrosal nerve and superficial petrosal nerve, C. Greater petrosal nerve and deep petrosal nerve, D. Greater petrosal nerve and external petrosal nerve
C: Greater petrosal nerve and deep petrosal nerve
Answer: C: Greater petrosal nerve and deep petrosal nerve 
Explanation: Greater petorsal nerve units with deep petrosal nerve to form nerve to pterygoid canal (also called vidian nerve).