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: Medicine
A 60 years old patient having cardiorespiratory arrest in hospital ward, for oxygenation what should be done immediately? 
Select and explain. 
A. Nasal intubation, B. Oral intubation, C. Cricothyroid membrane puncture, D. Tracheostomy
B: Oral intubation
Answer: B: Oral intubation 
Explanation: None