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: Anaesthesia
True regarding the rubens valve is 
Select and explain. 
A. Is a non-rebreathing valve, B. Will not allow spontaneous respiration, C. Is a pressure reducing valve, D. May jam in expiratory position
A: Is a non-rebreathing valve
Answer: A: Is a non-rebreathing valve 
Explanation: Rubens valve is a non – rebreathing valve used in self inflating resuscitation bags. It jams in inspiratory position occasionally. It allows spontaneous breathing .