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
Critical pH in Mendelson syndrome - 
Select and explain. 
A. 2.5, B. 3, C. 3.5, D. 4
A: 2.5
Answer: A: 2.5 
Explanation: • Critical pH value: 2.5
• Gastric pH of 2.5 or less with a gastric contents volume greater than 25 ml are critical values.
• Maximum pulmonary damage is achieved at an aspirate pH value of 1.5.