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: Surgery
Which of the following respiratory conditions is most alarming during patient sedation in dental clinic? 
Select and explain. 
A. Apnea, B. Dyspnea, C. Hyperapnea, D. Tachyopnea
A: Apnea
Answer: A: Apnea 
Explanation: None