This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: ABG Analysis Simplified, Subject name: Medicine
A patient has the following blood gases: PaCO2- 25, pH- 7.50, HCO3-- 19. Which of the following could not be the cause of this condition? 
Select and explain. 
A. Anxiety attack, B. paO2/Fi O2 ratio <100, C. Hysteria, D. Aspirin toxicity
B: paO2/Fi O2 ratio <100
Answer: B: paO2/Fi O2 ratio <100 
Explanation: First read pH always * Alkalotic pH * Low pCO2 * Low HCO3- Respiratory alkalosis paially compensated Caused by:- stimulate respiratory center - R.R | * Anxiety attack * Hysteria * Aspirin toxicity - stimulate respiratory center - R.R |