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: Physiology
Voluntary stage of deglutition is: 
Select and explain. 
A. Stage 1, B. Stage 2, C. Stage 3, D. All of the above.
A: Stage 1
Answer: A: Stage 1 
Explanation: Stage 1 is the oral phase and it is the voluntary stage of deglutition.